C++ Program to print the longest word of the string? - c++

#include <iostream>
#include <string>
using namespace std;
int main()
{
string s;
getline(cin , s) ; #input of string from user
int counter = 0;
int max_word = -1;
int len = s.length(); #length of string
string max = " ";
string counter_word = " ";
for (int i = 0; i < len; i++)
{
if(s[i] != ' ')
{
counter++;
}
if(s[i] == ' ' || i == len - 1)
{
if(counter > max_word)
{
max_word = counter;
//handling end of string.
if(i == len - 1)
max = s.substr(i + 1 - max_word, max_word); #sub string command that prints the longest word
else
max = s.substr(i - max_word, max_word);
}
counter = 0;
}
}
cout << max_word << " " << max << endl; #output
return 0;
}
The current output is '4 This' on entering the string "This is cool".
How do I get it to print '4 This; Cool' ?
On running it in Linux through the terminal, it gives me the error
" terminate called after throwing an instance of 'std::out_of_range' what(): basic_string::substr Aborted (core dumped) "

If I have understood you correctly then you mean the following
#include <iostream>
#include <sstream>
#include <string>
int main()
{
std::string s;
std::getline( std::cin, s );
std::string::size_type max_size;
std::string max_word;
std::string word;
std::istringstream is( s );
max_size = 0;
while ( is >> word )
{
if ( max_size < word.size() )
{
max_size = word.size();
max_word = word;
}
else if ( max_size == word.size() )
{
max_word += "; ";
max_word += word;
}
}
std::cout << max_size << ' ' << max_word << std::endl;
}
If to enter string
This is cool
then the output will be
4 This; cool

The basic idea here is to add each character to a temporary (initially empty) string until a space is encountered. At each instance of a space, the length of the temporary string is compared to the length of the "maxword" string, which is updated if it is found to be longer. The temporary string is emptied (reset to null using '\0') before proceeding to the next character in the input string.
#include <iostream>
#include <string>
using namespace std;
string LongestWord(string str) {
string tempstring;
string maxword;
int len = str.length();
for (int i = 0; i<=len; i++) {
if (tempstring.length()>maxword.length())
{
maxword=tempstring;
}
if (str[i]!=' ')
{
tempstring=tempstring+str[i];
}
else
{
tempstring='\0';
}
}
return maxword;
}
int main() {
cout << LongestWord(gets(stdin));
return 0;
}

#include <iostream>
using namespace std;
string longestWordInSentence(string str) {
// algorithm to count the number of words in the above string literal/ sentence
int words = 0;
for (int i = 0; i < str.length(); i++) {
if (str[i] == ' ') {
words++;
}
}
// incrementing the words variable by one as the above algorithm does not take into account the last word, so we are incrementing
// it here manually just for the sake of cracking this problem
words += 1; // words = 5
// words would be the size of the array during initialization since this array appends only the words of the above string
// and not the spaces. So the size of the array would be equal to the number of words in the above sentence
string strWords[words];
// this algorithm appends individual words in the array strWords
short counter = 0;
for (short i = 0; i < str.length(); i++) {
strWords[counter] += str[i];
// incrementing the counter variable as the iterating variable i loops over a space character just so it does not count
// the space as well and appends it in the array
if (str[i] == ' ') {
counter++;
}
}
// algorithm to find the longest word in the strWords array
int sizeArray = sizeof(strWords) / sizeof(strWords[0]); // length of the strWords array
int longest = strWords[0].length(); // intializing a variable and setting it to the length of the first word in the strWords array
string longestWord = ""; // this will store the longest word in the above string
for (int i = 0; i < sizeArray; i++) { // looping over the strWords array
if (strWords[i].length() > longest) {
longest = strWords[i].length();
longestWord = strWords[i]; // updating the value of the longestWord variable with every loop iteration if the length of the proceeding word is greater than the length of the preceeding word
}
}
return longestWord; // return the longest word
}
int main() {
string x = "I love solving algorithms";
cout << longestWordInSentence(x);
return 0;
}
I have explained every line of the code in great detail. Please refer to the comments in front of every line of code. Here is a generalized approach:
Count the number of words in the given sentence
Initialize a string array and set the size of the array equal to the number of words in the sentence
Append the words of the given sentence to the array
Loop through the array and apply the algorithm of finding the longest word in the string. It is similar to finding the longest integer in an array of integers.
Return the longest word.

My original solution contained a bug: If you were to input 2 words of length n and 1 word of length n + k, then it would output those three words.
You should make a separate if condition to check whether the word length is the same as before, if yes, then you can append "; " and the other word.
This is what I would do:
Change if(counter > max_word) to if(counter >= max_word) so words of the same length are also taken into account.
Make the max string by default (so "" instead of " "). (See next point)
Add an if condition in the if(counter >= max_word)second if condition to see if the max string is not empty, and if it's not empty append "; "
Changing max = to max += so that it appends the words (in the second condition)

Wouldn't it be easier for you to split the whole line into a vector of string ?
Then you could ask the length of each element of the string and then print them. Because right now you still have all the words in a single string making each individual word hard to analyse.
It would also be hard, as you requested, to print all the words with the same length if you use a single string.
EDIT :
Start by looping through your whole input
Keep the greater length of word between the current one and the previously saved
Make a substring for each word and push_back it into a vector
Print the length of the bigger word
Loop through the vector and print each word of that size.
Look the following website for all references about vectors. dont forget to #include
www.cplusplus.com/reference/vector/vector/

#include <iostream>
#include <vector>
#include <string>
void LongestWord(std::string &str){
std::string workingWord = "";
std::string maxWord = "";
for (int i = 0; i < str.size(); i++){
if(str[i] != ' ')
workingWord += str[i];
else
workingWord = "";
if (workingWord.size() > maxWord.size())
maxWord = workingWord;
}
std::cout << maxWord;
}
int main(){
std::string str;
std::cout << "Enter a string:";
getline(std::cin, str);
LongestWord(str);
std::cout << std::endl;
return 0;
}
Source: http://www.cplusplus.com/forum/beginner/31169/

#include<bits/stdc++.h>
using namespace std;
int main()
{
string s,a;
char ch;
int len,mlen=0;
getline(cin,s);
char* token=strtok(&s[0]," ");
string r;
while(token!=NULL)
{
r=token;
len=r.size();
if(mlen<len)
{
mlen=len;
a=token;
}
token = strtok(NULL, " ");
}
cout<<a;
return 0;
}

#include<iostream>
using namespace std;
int main()
{
string str;
getline(cin,str);
cin.ignore();
int len =str.length();`
int current_len=0,max_len=0;
int initial=0,start=0;
int i=0;
while(1)
{
if(i==len+2)
{break;}
if(str[i]==' '|| i==len+1)
{
if(current_len>max_len)
{
initial=start;
max_len=current_len;
}
current_len=0;
start=i+1;
}
else
{
current_len++;
}
i++;
}
for (int i = 0; i < max_len; i++)
{
cout<<str[i+initial];
}
cout<<endl<<max_len<<endl;
return 0 ;
}

Related

Removing all the vowels in a string in c++

I've written a code that removes all vowels from a string in c++ but for some reason it doesn't remove the vowel 'o' for one particular input which is: zjuotps.
Here's the code:
#include<iostream>
#include<string>
using namespace std;
int main(){
string s;
cin >> s;
string a = "aeiouyAEIOUY";
for (int i = 0; i < s.length(); i++){
for(int j = 0; j < a.length(); j++){
if(s[i] == a[j]){
s.erase(s.begin() + i);
}
}
}
cout << s;
return 0;
}
When I input: zjuotps
The Output I get is: zjotps
This is a cleaner approach using the C++ standard library:
#include <algorithm>
#include <iostream>
#include <string>
using namespace std;
int main()
{
std::string input = "zjuotps";
std::string vowels = "aeiouyAEIOUY";
auto predicate = [&vowels](char c) { return vowels.find(c) != std::string::npos; };
auto iterator = std::remove_if(input.begin(), input.end(), predicate);
input.erase(iterator, input.end());
cout << input << endl;
}
Edit:
as #RemyLebeau pointed out, std::erase_if can be used which is introduced in c++20 and the answer becomes one line of code:
std::erase_if(input, [&vowels](char c) { return vowels.find(c) != std::string::npos; });
You can develop a solution by adding the matching characters to the new string object. The eliminate() method writes the character to the result object if the characters in the input object doesn't match the characters in the remove object.
#include <iostream>
/**
* #brief This method scans the characters in the "input" object and writes
* the characters not in the "remove" object to the "result" object.
* #param input This object contains the characters to be scanned.
* #param remove This object contains characters that will not match.
* #param result Non-match result data is writed to this object.
*/
void eliminate(std::string input, std::string remove, std::string &result);
int main()
{
std::string input = "zjuotpsUK", remove = "aeiouyAEIOUY", result;
eliminate(input, remove, result);
std::cout << result << std::endl;
return 0;
}
void eliminate(std::string input, std::string remove, std::string &result)
{
for (size_t i = 0, j = 0; i < input.length(); i++)
{
for(j = 0; j < remove.length(); j++)
if(input[i] == remove[j])
break;
if(j == remove.length())
result += input[i];
}
}
In your code here, I replaced s with input_str, and a with vowels, for readability:
for (int i = 0; i < input_str.length(); i++){
for(int j = 0; j < vowels.length(); j++){
if(input_str[i] == vowels[j]){
input_str.erase(input_str.begin() + i);
}
}
}
The problem with your current code above is that each time you erase a char in the input string, you should break out of the vowels j loop and start over again in the input string at the same i location, checking all vowels in the j loop again. This is because erasing a char left-shifts all chars which are located to the right, meaning that the same i location would now contain a new char to check since it just left-shifted into that position from one position to the right. Erroneously allowing i to increment means you skip that new char to check in that same i position, thereby leaving the 2nd vowel in the string if 2 vowels are in a row, for instance. Here is the fix to your immediate code from the question:
int i = 0;
while (i < s.length()){
bool char_is_a_vowel = false;
for(int j = 0; j < a.length(); j++){
if(s[i] == a[j]){
char_is_a_vowel = true;
break; // exit j loop
}
}
if (char_is_a_vowel){
s.erase(s.begin() + i);
continue; // Do NOT increment i below! Skip that.
}
i++;
}
However, there are many other, better ways to do this. I'll present some below. I personally find this most-upvoted code difficult to read, however. It requires extra study and looking up stuff to do something so simple. So, I'll show some alternative approaches to that answer.
Approach 1 of many: copy non-vowel chars to new string:
So, here is an alternative, simple, more-readable approach where you simply scan through all chars in the input string, check to see if the char is in the vowels string, and if it is not, you copy it to an output string since it is not a vowel:
Just the algorithm:
std::string output_str;
for (const char c : input_str) {
if (vowels.find(c) == std::string::npos) {
output_str.push_back(c);
}
}
Full, runnable example:
#include <iostream> // For `std::cin`, `std::cout`, `std::endl`, etc.
#include <string>
int main()
{
std::string input_str = "zjuotps";
std::string vowels = "aeiouyAEIOUY";
std::string output_str;
for (const char c : input_str)
{
if (vowels.find(c) == std::string::npos)
{
// char `c` is NOT in the `vowels` string, so append it to the
// output string
output_str.push_back(c);
}
}
std::cout << "input_str = " << input_str << std::endl;
std::cout << "output_str = " << output_str << std::endl;
}
Output:
input_str = zjuotps
output_str = zjtps
Approach 2 of many: remove vowel chars in input string:
Alternatively, you could remove the vowel chars in-place as you originally tried to do. But, you must NOT increment the index, i, for the input string if the char is erased since erasing the vowel char left-shifs the remaining chars in the string, meaning that we need to check the same index location again the next iteration in order to read the next char. See the note in the comments below.
Just the algorithm:
size_t i = 0;
while (i < input_str.length()) {
char c = input_str[i];
if (vowels.find(c) != std::string::npos) {
input_str.erase(input_str.begin() + i);
continue;
}
i++;
}
Full, runnable example:
#include <iostream> // For `std::cin`, `std::cout`, `std::endl`, etc.
#include <string>
int main()
{
std::string input_str = "zjuotps";
std::string vowels = "aeiouyAEIOUY";
std::cout << "BEFORE: input_str = " << input_str << std::endl;
size_t i = 0;
while (i < input_str.length())
{
char c = input_str[i];
if (vowels.find(c) != std::string::npos)
{
// char `c` IS in the `vowels` string, so remove it from the
// `input_str`
input_str.erase(input_str.begin() + i);
// do NOT increment `i` here since erasing the vowel char above just
// left-shifted the remaining chars in the string, meaning that we
// need to check the *same* index location again the next
// iteration!
continue;
}
i++;
}
std::cout << "AFTER: input_str = " << input_str << std::endl;
}
Output:
BEFORE: input_str = zjuotps
AFTER: input_str = zjtps
Approach 3 of many: high-speed C-style arrays: modify input string in-place
I borrowed this approach from "Approach 1" of my previous answer here: Removing elements from array in C
If you are ever in a situation where you need high-speed, I'd bet this is probably one of the fastest approaches. It uses C-style strings (char arrays). It scans through the input string, detecting any vowels. If it sees a char that is NOT a vowel, it copies it into the far left of the input string, thereby modifying the string in-place, filtering out all vowels. When done, it null-terminates the input string in the new location. In case you need a C++ std::string type in the end, I create one from the C-string when done.
Just the algorithm:
size_t i_write = 0;
for (size_t i_read = 0; i_read < ARRAY_LEN(input_str); i_read++) {
bool char_is_a_vowel = false;
for (size_t j = 0; j < ARRAY_LEN(input_str); j++) {
if (input_str[i_read] == vowels[j]) {
char_is_a_vowel = true;
break;
}
}
if (!char_is_a_vowel) {
input_str[i_write] = input_str[i_read];
i_write++;
}
}
input_str[i_write] = '\n';
Full, runnable example:
#include <iostream> // For `std::cin`, `std::cout`, `std::endl`, etc.
#include <string>
/// Get the number of elements in an array
#define ARRAY_LEN(array) (sizeof(array)/sizeof(array[0]))
int main()
{
char input_str[] = "zjuotps";
char vowels[] = "aeiouyAEIOUY";
std::cout << "BEFORE: input_str = " << input_str << std::endl;
// Iterate over all chars in the input string
size_t i_write = 0;
for (size_t i_read = 0; i_read < ARRAY_LEN(input_str); i_read++)
{
// Iterate over all chars in the vowels string. Only retain in the input
// string (copying chars into the left side of the input string) all
// chars which are NOT vowels!
bool char_is_a_vowel = false;
for (size_t j = 0; j < ARRAY_LEN(input_str); j++)
{
if (input_str[i_read] == vowels[j])
{
char_is_a_vowel = true;
break;
}
}
if (!char_is_a_vowel)
{
input_str[i_write] = input_str[i_read];
i_write++;
}
}
// null-terminate the input string at its new end location; the number of
// chars in it (its new length) is now equal to `i_write`!
input_str[i_write] = '\n';
std::cout << "AFTER: input_str = " << input_str << std::endl;
// Just in case you need it back in this form now:
std::string str(input_str);
std::cout << " C++ str = " << str << std::endl;
}
Output:
BEFORE: input_str = zjuotps
AFTER: input_str = zjtps
C++ str = zjtps
See also:
[a similar answer of mine in C] Removing elements from array in C

Find and output longest string word c++

I'm pretty new to programming and recently started working with strings. In my mind, this idea should somewhat work, but I have no idea what's wrong.
So I go through the string, with simb++ (to find length of the word) and where++ (to find where in the string am I) until I find a space, where I compare with the longest word I've found so so far (temp) and if it's longer, I make it the longest and find starting point of the word (start). When the for(...) ends, I write the word in the last for()
#include <iostream>
#include <string>
using namespace std;
int main()
{
string sentence;
string longest="";
int simb=0;
int temp=0;
int where=0;
int start=0;
cout<<"Input sentence"<<endl;
getline(cin,sentence);
for(int i=0 ; i<sentence.size() ; i++)
{
if(sentence[i]!=' ')
{
simb++;
where++;
}
if(sentence[i]==' ')
{
if(simb>temp)
{
where++;
simb++;
start=where-simb;
temp=simb;
}
simb=0;
}
}
for(int m=start ; m<=temp ; m++)
{
longest=longest+sentence[m];
}
cout<<"longest sentence"<<longest<<endl;
return 0;
}
There are a number of issues in your code:
if simb<=temp you don't increment where, you can just remove where completely and use i instead.
incrementing simb before calculating start results in start being 1 less than it should be
you don't check the length of last word in the string (assuming the string doesn't end with whitespace)
your final for loop goes from start to temp but should go from start to start + temp
Fixing these issues gives:
#include <iostream>
#include <string>
using namespace std;
int main()
{
string sentence;
int simb = 0;
int temp = 0;
int start = 0;
string sentence = "test test2 test 3 test 4 foo longest";
for (int i = 0; i <= sentence.size(); i++)
{
if (i != sentence.size() && sentence[i] != ' ')
{
simb++;
}
else
{
if (simb > temp)
{
start = i - simb;
temp = simb;
}
simb = 0;
}
}
string longest = "";
for (int m = start; m < start + temp; m++)
{
longest = longest + sentence[m];
}
cout << "longest sentence: '" << longest << "'\n";
return 0;
}
Note that using std::istringstream would be much simpler:
#include <iostream>
#include <string>
#include <sstream>
int main()
{
std::string sentence = "test test2 test 3 test 4 foo longest";
std::string longest;
std::stringstream ss(sentence);
std::string word;
while (ss >> word)
{
if (word.length() > longest.length())
{
longest = word;
}
}
std::cout << "longest sentence: '" << longest << "'\n";
return 0;
}
You can try this:
1.first locate where the spaces are.
2.calculate the gap between the two consequent words/strings.
3.find the word which has the maximum gap.
4.the world which has the maximum gap will be the longest one.
It's not c++ specific you can try this with any language.
Here is the c++ example:
#include <iostream>
#include <string>
using namespace std;
int main(){
//to get the user input
cout<<"Enter a sentence:"<<endl;
string s;
getline(cin,s);
// here the old value refers to the last index having space
// gap is the difference betweeen latest index having space and the old value
// max stores the maximum gap
int old=0;
int max=0;
int gap=0;
//these two values store the starting and ending index of longest string
int startIndex;
int endIndex;
// This for loop determines the maximum gap and calculates the starting
// and ending index of the longest word.
for(int i=0;i<s.size();i++){
if(isspace(s[i])|| i==s.size()){
if((i-old)>gap){
max=(i-old);
startIndex=i-max;
endIndex=i;}
gap=(i-old);
old=i+1;}
}
cout<<"longest string in the sentence is:";
//here we are using the determined starting and ending indices to print the longest word
for(int i=startIndex;i<=endIndex;i++){
cout<<s[i];
}
return 0;
}

C++ word count program using C Strings errors out after program runs

I am having problems with the following code once the string gets to around 24~ characters. It will run through the code just fine and calculate the correct amount of words in the string but it will error on strings containing more than a few words. You can try inputting your name in 3 or 4 times and it errors out for me. I ran the debug option and it shows the error at line 74 which is the last closing bracket for the main function.
#include <iostream>
using namespace std;
class WordCounter
{
private:
string tempInput;
int wordCount;
int arraySize;
char characterArray[];
public:
WordCounter()
{
tempInput = "";
wordCount = 0;
arraySize = 0;
}
void getCharString()
{
cout << "Enter the sentence you would like a word count for:\n";
getline(cin, tempInput);
}
void setArraySize()
{
arraySize = tempInput.length();
}
void convertStringToCharArray()
{
for(int counter = 0; counter < arraySize; counter++)
{
characterArray[counter] = tempInput[counter];
}
}
int countNumOfWords()
{
int charCount;
for(int counter = 0; counter < arraySize; counter++)
{
if(characterArray[counter] == '\n')
{
return 0;
}
if(characterArray[counter] == ' ')
{
charCount = 0;
}
else if(++charCount == 1)
{
wordCount++;
}
}
return wordCount;
}
};
int main()
{
WordCounter wordOne;
wordOne.getCharString();
wordOne.setArraySize();
wordOne.convertStringToCharArray();
int numberOfWords = wordOne.countNumOfWords();
cout << "The number of words in the sentence is " << numberOfWords << ".\n";
return 0;
}
If you want a function that count words in a string, where words are splited by whitespaces character, you can just use a regex :
#include <string>
#include <regex>
size_t countNumOfWords(std::string s) {
std::regex wordCountRegex("[^ ]+");
std::smatch matches;
size_t nb_words = 0;
while (std::regex_search(s, matches, wordCountRegex)) {
s = matches.suffix().str();
++nb_words;
}
return nb_words;
}
Or continue with the same code you had before :
int countNumOfWords(const std::string& s)
{
int charCount;
for(int counter = 0; counter < s.length(); counter++)
{
if(s[counter] == '\n')
{
return 0;
}
if(s[counter] == ' ')
{
charCount = 0;
}
else if(++charCount == 1)
{
wordCount++;
}
}
return wordCount;
}
However, if you want to continue using your code, you will have to make several modifications :
The field characterArray is never initialized, and no memory allocation is done. The value of characterArray ( which is a pointer to char ) is completely random, and accessing it through the subscript operator results in undefined behavior ( which means that the program could crash, or corrupt variables, or do nothing detectable, and that make debugging very hard ). You might want to add characterArray = new char[arraySize]; in the convertStringToCharArray() method
Speaking about converting std::string to char array, you might want to replace the code in the convertStringToCharArray() method by that : characterterArray = tempInput.c_str(). std::string::c_str() method return the internal value of the pointer in your std::string object, and points to the memory location where a char array has been allocated. You should not delete it
Based on the previous point, you might want to only use the std::string field, which has his own size information ( making arraySize field useless ) and his own char array ( making characterArray field useless ).

C++ find words with first and last same letter and sort them in alphabetical order

i can't make program that reads from file words ( there is no limit of words or length to them ) with same first letter and last. I use class and object and first of all i can't make reading them
#include <iostream>
#include <string>
#include <sstream>
#include <fstream>
using namespace std;
class Texts{
public:
void Realding(string &All);
void Searching(string &text, char *Word);
};
int main()
{
Texts A;
string Text; char word[40];
A.Reading(Text);
A.Searching(Text, word);
system("PAUSE");
}
void Texts::Reading(string &All)
{
string temp;
ifstream read("Text.txt");
while (getline(read, temp)) { All += temp; All += "\n"; }
cout << All;
}
void Texts::Searching(string &text, char *Word)
{
int i = 0;
int j = 0;
int letters = 0;
int zodz = 0;
int index = 0;
while (1)
{
if (text[i] == ' ' || text[i] == '\0')
{
zodz++;
if (text[0] == text[i - 1])
{
letters = j;
for (int l = 0; l < letters; l++)
{
//cout << text[l];
}
j = 0;
}
if (text[i + 1 - j] == text[i - 1])
{
letters = j;
for (int l = i - j; l < letters; l++)
{
// cout << text[l];
}
j = 0;
}
}
if (text[i] == '\0') break;
else
i++;
j++;
}
}
I can't make it properly read from file... Text.txt looks like
asdfa su egze hah ktis faf
And how later when selected words with first and last same letter to assign to array, that later to sort them in alphabetical order. Thanks if someone helps me.
Reading from file:
std::ifstream in(NameOfFile);
std::string word;
while (in >> word) //will stop when word can't be read. probably bad file or end of file
{
// do something with word
}
Find word with same first and last letter
if (word.front() == word.back())
{
// do something with word
}
Note this does not handle words with capitalized letters. It would not find "Mom". It will likely crash over empty words. Both have trivial fixes.
Assign word to array
array[index++] == word;
This assumes you want to advance the index after inserting into the array. Please note the program will behave poorly if the array is overfilled. If you are allowed to by the assignment, please consider using a std::vector.
Sorting the array
std::sort(array, array + index);
This assumes you are allowed to use std::sort. Again, if possible use a std::vector in place of the array. index is assumed to be the value of index from the adding example above after all of the adding has been done. If you are NOT allowed to use std::sort ask another question. It's a lengthy topic.

Reverse words of a sentence in c++, Asked on Google Code jam

How to solve this? https://code.google.com/codejam/contest/351101/dashboard#s=p1?
The code I ended up with is below, but it can only reverse strings up to one space because it was code keeping the literal logic in mind, Reverse the whole string, reverse the words, and done. The spaces are slightly messed up and when I tried a loop to detect number of spaces and act accordingly it failed. Please help! Code:
#include <iostream>
#include <string>
using namespace std;
int main()
{
char revwrd[100];
char revstr[100];
string str;
getline(cin, str);
cout<<str;
int sps[10];
int len,y=0;
len = str.length();
cout<<"\n"<<"The Length of the string is:"<<len;
for(int x=len-1;x>-1;x--)
{
revstr[x] = str[y];
y++;
}
cout<<"\n"<<"The inverse of the string is:"<<"\n";
for(int z = 0;z<len;z++)
{
cout<<revstr[z];
}
cout<<"\n";
int no=0;
int spaces=0;
for(int a=0;a<len;a++)
{
if(revstr[a]== ' ')
{
sps[no]=a;
no++;
spaces++;
}
}
int rinc=0;
int spinc;
cout<<"\n";
spinc=sps[0];
int spinc2 = sps[0]+1;
int lend;
for(rinc=0;rinc<sps[0]+1;rinc++)
{
revwrd[rinc] = revstr[spinc];
spinc--;
}
for(lend=len;lend>sps[0];lend--)
{
revwrd[spinc2] = revstr[lend];
spinc2++;
}
cout<<"Spaces in the string:"<<spaces<<"\n";
cout<<"The words inversed are:"<<"\n";
for(int inc=1;inc<len+1;inc++)
{
cout<<revwrd[inc];
}
return 0;
}
The conditions of the challenge are that there is only a single space between words, and that spaces don't appear at the beginning or the end of the line, so for this particular exercise you don't have to worry about preserving spacing; as long as you write the output with a single space between each word, you're good.
With that in mind, you can read each word using regular formatted input:
std::string word;
...
while ( stream >> word )
// do something with word
You don't have to worry about buffer size, you don't have to worry about detecting spaces, etc. You do have to worry about detecting the newline character, but that's easily done using the peek method:
while ( stream >> word )
{
// do something with word;
if ( stream.peek() == '\n' )
break;
}
The above loop will read individual words from the input stream stream until it sees a newline character (there's probably a better way to do that, but it works).
Now, in order to reverse each line of input, you obviously need to store the strings somewhere as you read them. The easiest thing to do is store them to a vector:
std::vector< std::string > strings;
...
while ( stream >> word )
{
strings.push_back( word );
if ( stream.peek() == '\n' )
break;
}
So now you have a vector containing all the strings in the line, you just have to print them out in reverse order. You can use a reverse iterator to walk through the vector:
std::vector< std::string >::reverse_iterator it;
for ( it = strings.rbegin(); it != strings.rend(); ++it )
{
std::cout << *it << " ";
}
std::cout << std::endl;
The rbegin() method returns an iterator that points to the last element in the vector; the rend() method returns an iterator that points to an element before the first element of the vector; ++it advances the iterator to point to the next item in the vector, going back to front; and *it gives the string that the iterator points to. You can get a little more esoteric and use the copy template function:
std::copy( strings.rbegin(),
strings.rend(),
std::ostream_iterator<std::string>( std::cout, " " )
);
That single method call replaces the loop above. It creates a new ostream_iterator that will write strings to cout, separated by a single space character.
For the conditions of this particular exercise, this is more than adequate. If you were required to preserve spacing, or to account for punctuation or capitalization, then you'd have to do something a bit lower-level.
Just few loops and if's:
// Reverse Words
#include <iostream>
#include <string>
using namespace std;
int main() {
int tc; cin >> tc; cin.get();
for(int t = 0; t < tc; t++) {
string s, k; getline(cin, s);
for(int i = (s.length()- 1); i >= 0; i--) {
if(s[i] == ' ' || (i == 0)) {
if(i == 0) k += ' ';
for(int j = i; j < s.length(); j++) {
k += s[j];
if(s[j+1] == ' ' ) break;
}
}
}
cout << "Case #" << t + 1 << " " << k << endl;
}
return 0;
}
This might handle multi spaces:
std::string ReverseSentence(std::string in)
{
std::vector<string> words;
std::string temp = "";
bool isSpace = false;
for(int i=0; in.size(); i++)
{
if(in[i]!=' ')
{
if(isSpace)
{
words.push_back(temp);
temp = "";
isSpace = false;
}
temp+=in[i];
}
else
{
if(!isSpace)
{
words.push_back(temp);
temp = "";
isSpace = true;
}
temp += " ";
}
}
std::reverse(words.begin(),words.end());
std::string out = "";
for(int i=0; i<words.size(); i++)
{
out+=words[i];
}
return out;
}
you can follow this method :
step 1 : just check for spaces in input array store their index number in an integer array.
step 2 : now iterate through this integer array from end
step a : make a string by copying characters from this index to previous index .
note : since for first element there is no previous element in that case you will copy from this index to end of the input string .
step b : step a will give you a word from end of input string now add these word with a space to make your output string .
I hope this will help you .
This problem is really made for recursion:
void reverse()
{
string str;
cin >> str;
if (cin.peek() != '\n' || cin.eof()) {
str = " " + str;
reverse();
}
cout << str;
}
int main(int argc, const char * argv[])
{
int count = 0;
cin >> count;
for (int i = 0; i < count; i++) {
cout << "Case #" << (i + 1) << ": ";
reverse();
cout << endl;
}
return 0;
}
So I read word by word and add one space in front of the word until end of line or file is reached. Once end of line is reached the recursion unwraps and prints the read strings in reversed order.
I went for the brute force, and I badly wanted to use pointers!
get the sentence
detect every word and put them in a container.
read backwards the container.
This is it:
#include <iostream>
#include <string>
#include <vector>
int main()
{
char *s1 = new char[100];
std::cin.getline(s1, 100);
std::vector<std::string> container;
char* temp = new char[100];
char *p1, *p0;
p1 =p0 = s1;
int i;
do{
if (*p1==' ' || *p1=='\0'){
//std::cout<<p1-p0<<' ';
for(i=0;i<p1-p0;++i) temp[i]=p0[i]; temp[i]='\0';
p0 = p1+1;
container.push_back(temp);
std::cout<<temp;
}
p1++;
}while(*(p1-1)!='\0');
std::cout<<std::endl;
for(int i=container.size()-1;i>=0;i--) std::cout<<container[i]<<' ';
return 0;
}