This program takes a line, separates each word and adds them into a vector. But while printing the strings from vector after the first word all the remaining words contain a whitespace character at the beginning. I want those whitespaces to be removed.
#include <iostream>
#include <string>
#include <vector>
using namespace std;
void addmember(string s) {
vector<string> vlist;
string buf;
for(int i = 0; i < s.length(); i++) {
if(s[i] == ' ') {
buf.push_back('\0');
vlist.push_back(buf);
buf.erase();
}
buf.push_back(s[i]);
}
for(auto it : vlist) {
cout << it << "\t" << it.size() << endl;
}
}
int main() {
string s = "A friend is someone who knows all about you";
addmember(s);
return 0;
}
Output:
A
friend
is
someone
who
knows
all
about
You push the character onto the buf string even if it is a whitespace.
Put buf.push_back(s[i]) in a else branch.
for (int i = 0; i < s.length(); i++) {
if (s[i] == ' ') {
vlist.push_back(buf);
buf.erase();
}
else {
buf.push_back(s[i]);
}
}
Edit: As you use strings in the vector as well as cout << and not char*/char[] one can assume you only want C++ style strings.
If so, you should also remove the insertion of \0 terminators at the end of each substring. C++ strings are not zero terminated.
You push_back() every s[i], no matter what it is. You want to do that only if s[i] is not a space:
for(int i=0; i<s.length(); i++){
if(s[i] == ' '){
vlist.push_back(buf);
buf.erase();
} else {
buf.push_back(s[i]);
}
}
Related
I wrote this code to detect if an input string has a space or not. Please tell what is wrong in this approach.
#include <iostream>
#include <string>
using namespace std;
int main(){
string inp;
getline(cin, inp);
for (int i = 0; i < inp.length(); i++) {
string z = to_string(inp[i]);
if (z == " ") {
cout << "space";
}
else {
i++;
}
}
}
If i enter a string with spaces, it doesn't print "space".
Since inp is an std::string, inp[i] will be a char. Since std::to_string only has overloads for arithmetic, non-char values, calling it on a char is akin to calling it on the integer representation of said char. (If you log z, you'll likely find a number printed.)
Instead, directly compare inp[i] to a space. else { i++; } is also unnecessary – you may be jumping over spaces.
for (int i = 0; i < inp.length(); i++) {
if (inp[i] == ' ') { // note single quotes for char
cout << "space";
}
}
#TrebledJ's answer explains why your code is broken and how to fix it.
Another way to handle this situation is to use std::string::find() instead:
#include <iostream>
#include <string>
int main(){
std::string inp;
std::getline(std::cin, inp);
if (inp.find(' ') != std::string::npos) {
std::cout << "space";
}
}
Alternatively, your original code tries to output "space" for each space character found. You could use find() in a loop:
#include <iostream>
#include <string>
int main(){
std::string inp;
std::getline(std::cin, inp);
std::string::size_type idx = inp.find(' ');
while (idx != std::string::npos) {
std::cout << "space at " << idx << std::endl;
idx = inp.find(' ', idx+1);
}
}
I have a program that reverses the letters in a sentence but keeps the words in the same order. I need to change the code from an iostream library to an fstream library where the user inputs a sentence into an input file("input.txt") and the program outputs the reverse into an output text file.
example of input:
This problem is too easy for me. I am an amazing programmer. Do you agree?
Example of output:
sihT melborp si oot ysae rof em. I ma na gnizama remmargorp. oD uoy eerga?
The code I already have:
int main()
{
int i=0, j=0, k=0, l=0;
char x[14] = "I LOVE CODING";
char y[14] = {'\0'};
for(i=0; i<=14; i++) {
if(x[i]==' ' || x[i]=='\0') {
for(j=i-1; j>=l; j--)
y[k++] = x[j];
y[k++] = ' ';
l=i+1;
}
}
cout << y;
return 0;
}
I would use std::string to store the string, and benefit from std::vector and const_iterator to make better use of C++ features:
#include <string>
#include <vector>
int main()
{
std::string s("This problem is too easy for me. I am an amazing programmer. Do you agree?");
const char delim = ' ';
std::vector<std::string> v;
std::string tmp;
for(std::string::const_iterator i = s.begin(); i <= s.end(); ++i)
{
if(*i != delim && i != s.end())
{
tmp += *i;
}else
{
v.push_back(tmp);
tmp = "";
}
}
for(std::vector<std::string>::const_iterator it = v.begin(); it != v.end(); ++it)
{
std::string str = *it,b;
for(int i=str.size()-1;i>=0;i--)
b+=str[i];
std::cout << b << " ";
}
std::cout << std::endl;
}
Output:
sihT melborp si oot ysae rof .em I ma na gnizama .remmargorp oD uoy ?eerga
The code that you submitted looks much more like something from C rather than from C++. Not sure if you are familiar std::string and function calls. As the code you wrote is pretty sophisticated, I will assume that you are.
Here is an example of how to use fstream. I almost always you getline for the input because I find that it gets me into fewer problems.
I then almost always use stringstream for parsing the line because it neatly splits the lines at each space.
Finally, I try to figure out a while() or do{}while(); loop that will trigger off of the input from the getline() call.
Note that if the word ends in a punctuation character, to keep the punctuation at the end, the reverse_word() function has to look for non-alpha characters at the end and then save that aside. This could be done by only reversing runs of alphas.
#include <iostream>
#include <fstream>
#include <string>
#include <sstream>
///////////////////
/// return true if ch is alpha
/// return false for digits, punctuation, and all else
bool is_letter(char ch){
if((ch >= 'A' && ch <= 'Z') ||
(ch >= 'a' && ch <= 'z')) {
return true;
} else {
return false;
}
}
////////
// Only reverse the letter portion of each word
//
std::string reverse_word(std::string str)
{
std::string output_str; // Probably have to create a copy for output
output_str.reserve(str.length()); // reserve size equal to input string
// iterate through each letter of the string, backwards,
// and copy the letters to the new string
char save_non_alpha = 0;
for (auto it = str.rbegin(); it != str.rend(); it++) {
/// If the last character is punctuation, then save it to paste on the end
if(it == str.rbegin() && !is_letter(*it)) {
save_non_alpha = *it;
} else {
output_str += *it;
}
}
if(save_non_alpha != 0) {
output_str += save_non_alpha;
}
return output_str; // send string back to caller
}
int main()
{
std::string input_file_name{"input.txt"};
std::string output_file_name{"output.txt"};
std::string input_line;
std::ifstream inFile;
std::ofstream outFile;
inFile.open(input_file_name, std::ios::in);
outFile.open(output_file_name, std::ios::out);
// if the file open failed, then exit
if (!inFile.is_open() || !outFile.is_open()) {
std::cout << "File " << input_file_name
<< " or file " << output_file_name
<< " could not be opened...exiting\n";
return -1;
}
while (std::getline(inFile, input_line)) {
std::string word;
std::string sentence;
std::stringstream stream(input_line);
// I just like stringstreams. Process the input_line
// as a series of words from stringstream. Stringstream
// will split on whitespace. Punctuation will be reversed with the
// word that it is touching
while (stream >> word) {
if(!sentence.empty()) // add a space before all but the first word
sentence += " ";
word = reverse_word(word);
sentence += word;
}
outFile << sentence << std::endl;
}
inFile.close();
outFile.close();
return 0;
}
I am trying to make a program in which a user enters a string and i will print out the second word in the string with its size.
The delimiter's are space( ), comma(,) and tab( ).
I have used a character array and fgets to read from user and a character pointer that points to the first element of the array.
source code:
#include"iostream"
#include<stdio.h>
#include<string>
using namespace std;
// extract the 2nd word from a string and print it with its size(the number of characters in 2nd word)
int main()
{
char arr[30], arr1[30];
char *str = &arr1[0];
cout<<"Enter a string: ";
fgets(str, 30, stdin);
int i = 0, j, count = 1, p = 0; // count is used to find the second word
// j points to the next index where the first delimiter is found.
// p is used to store the second word found in character array 'arr'
while(*(str+i) != '\n')
{
if(*(str+i) == ' ' || *(str+i) == ',' || *(str+i) == ' ')
{
count++;
if(count == 2)
{
// stroing 2nd word in arr character array
j = i+1;
while(*(str+j) != ' ' || *(str+j) != ',' || *(str+j) != ' ')
{
arr[p] = *(str+j);
cout<<arr[p];
p++;
i++;
j++;
}
break;
}
}
i++;
}
arr[p+1] = '\0'; // insert NULL at end
i = 0;
while(arr[i] != '\0')
{
cout<<arr[i];
i++;
}
cout<<"("<<i<<")"<<endl;
return 0;
}
Help me out with this.
To start, don't use std::cin for testing. Just set a value in your code for consistency and ease of development. Use this page for a reference.
#include <iostream>
#include <string>
int main() {
std::string str("this and_that are the tests");
auto start = str.find_first_of(" ,\n", 0);
auto end = str.find_first_of(" ,\n", start + 1);
std::cout << str.substr(start, end - start);
return 0;
}
And this is still somewhat of a hack, it just depends where you are going. For instance the Boost library is rich with extended string manipulation. If you are going to parse out more than just one word it can still be done with string manipulations, but ad-hoc parsers can get out of hand. There are other tools like Boost Spirit to keep code under control.
The delimiters used when extracting from a stream depends on the locale currently in effect. One (cumbersome) way to change the extraction behaviour is to create a new locale with a special facet in which you specify your own delimiters. In the below example the new locale is used to imbue a std::stringstream instead of std::cin directly. The facet creation part is mostly copy/paste from other answers here on SO, so you'll find plenty of other examples.
#include <iostream>
#include <locale> // std::locale, std::ctype<char>
// https://en.cppreference.com/w/cpp/locale/ctype_char
#include <sstream> // std::stringstream
#include <algorithm> // std::copy_n
#include <vector> // a container to store stuff in
// facet to create our own delimiters
class my_facet : public std::ctype<char> {
mask my_table[table_size];
public:
my_facet(size_t refs = 0)
: std::ctype<char>(&my_table[0], false, refs)
{
// copy the "C" locales table to my_table
std::copy_n(classic_table(), table_size, my_table);
// and create our delimiter specification
my_table[' '] = (mask)space;
my_table['\t'] = (mask)space;
my_table[','] = (mask)space;
}
};
int main() {
std::stringstream ss;
// create a locale with our special facet
std::locale loc(std::locale(), new my_facet);
// imbue the new locale on the stringstream
ss.imbue(loc);
while(true) {
std::string line;
std::cout << "Enter sentence: ";
if(std::getline(std::cin, line)) {
ss.clear(); // clear the string stream from prior errors etc.
ss.str(line); // assign the line to the string stream
std::vector<std::string> words; // std::string container to store all words in
std::string word; // for extracting one word
while(ss>>word) { // extract one word at a time using the special facet
std::cout << " \"" << word << "\" is " << word.size() << " chars\n";
// put the word in our container
words.emplace_back(std::move(word));
}
if(words.size()>=2) {
std::cout << "The second word, \"" << words[1] << "\", is " << words[1].size() << " chars\n";
} else {
std::cout << "did not get 2 words or more...\n";
}
} else break;
}
}
#include"iostream"
#include<stdio.h>
#include<string>
#include <ctype.h>
using namespace std;
int main()
{
char c;
string str;
char emp = ' ';
cout<<"Enter a string: ";
getline (cin,str);
int j = 0, count = 1, counter = 0;
for (int i = 0; i < str.length() && count != 2; i++)
{
cout<< str[i] <<endl;
if( isspace(str[i]) || str[i] == ',' || str[i] == '\t' )
{
count++;
if(count == 2)
{
j = i+1;
while(j < str.length())
{
if (isspace(str[j]) || str[j] == ',' || str[j] == '\t')
{
break;
}
cout<<str[j];
counter++;
j++;
}
cout<<endl;
}
}
}
cout<<"size of the word: "<<counter<<endl;
return 0;
}
This is a simple answer to what you want, hope to help you.
// Paul Adrian P. Delos Santos - BS Electronics Engineering
// Exercise on Strings
#include <iostream>
#include <sstream>
using namespace std;
int main(){
// Opening Message
cout << "This program will display the second word and its length.\n\n";
// Ask for a string to the user.
string input;
cout << "Now, please enter a phrase or sentence: ";
getline(cin, input);
// Count the number of words to be used in making a string array.
int count = 0;
int i;
for (i=0; input[i] != '\0'; i++){
if (input[i] == ' ')
count++;
}
int finalCount = count + 1;
// Store each word in a string array.
string arr[finalCount];
int j = 0;
stringstream ssin(input);
while (ssin.good() && j < finalCount){
ssin >> arr[j];
j++;
}
// Display the second word and its length.
string secondWord = arr[1];
cout << "\nResult: " << arr[1] << " (" << secondWord.size() << ")";
return 0;
}
I need to use a character array pointing to a function. In the function, I need it to make the input into all capital letters. I figured I'd use the toupper function, which worked great for certain input, but when I input certain words I end up getting weird symbols/numbers in the end of my output(see output). Any help?
Code
#include <iostream>
#include <cstring>
#include <string>
using namespace std;
void allUppercase(char*);
const int SIZE = 50;
int main()
{
char words[SIZE];
cout << "Please enter your text : ";
cin.get(words, (SIZE-1));
cout << "The keyboard input was \"" << words << "\".\n";
cout << "\nThe uppercase output is \"";
allUppercase(words);
cout << "\".\n";
return 0;
}
// outputs the string entered in uppercase letters
// (Use a character array to store the string)
void allUppercase(char *ch)
{
char temp[SIZE];
for (int i=0; i < SIZE; i++)
{
if (ch[i] != '\0')
temp[i] = toupper(ch[i]);
else
break;
}
cout << temp;
}
Example Output
You forgot to null terminate temp.
void allUppercase(char *ch) {
char temp[SIZE];
for (int i=0; i < SIZE; i++) {
if (ch[i] != '\0') {
temp[i] = toupper(ch[i]);
} else {
temp[i] = '\0';
break;
}
}
cout << temp;
}
You just need to add a zero byte at the end of the result string.
For example,
void allUppercase( char const* s )
{
char temp[SIZE];
int i = 0;
while( temp[i] = toupper( s[i] ) ) { ++i; }
cout << temp;
}
Disclaimer: code not touched by compiler.
In other news, in order to work with national characters such as Norwegian æ, ø and å, with a single byte per character encoding that supports them, you need to
cast the argument to toupper to unsigned char, and
call setlocale( LC_ALL, "" ) at the start of main.
Without the cast toupper can receive a negative argument value other than EOF, because char is usually a signed type, and in that case the behavior is undefined (e.g. a crash).
Also, instead of raw arrays and pointers, just use std::string. You have already included the <string> header.
the best way is to write a while loop like this
while(ch[i]!='\0')
{
temp[i] = toupper(ch[i]);
cout<<temp[i]
i++;
}
and this program will be terminated when '\0' is found
how can I print a single word from a string in each line with the number of characters right next to it and the average of the characters together? I'm suppose to use a string member function to convert the object into a c string. The function countWords accepts the c string and returns an int. The function is suppose to read in each word and their lengths including the average of characters. I have done how much words are in the string except I don't know how continue the rest.
For example: super great cannon boys
super 5
great 5
cannon 6
boys 4
average of characters: 5
This is my program so far:
#include <iostream>
#include <string>
#include <cstring>
using namespace std;
int countWords(char *sentence);
int main()
{
const int size=80;
char word[size];
double average=0;
cout<<"Enter words less than " <<size-1<<" characters."<<endl;
cin.getline(word, size);
cout <<"There are "<<countWords(word)<<" words in the sentence."<<endl;
return 0;
}
int countWords(char *sentence)
{
int words= 1;
while(*sentence != '\0')
{
if(*sentence == ' ')
words++;
sentence++;
}
return words;
}
Unless this is something like homework that prohibits doing so, you almost certainly want to use std::string along with the version of std::getline that works with a std::string instead of a raw buffer of char:
std::string s;
std::getline(std::cin, s);
Then you can count the words by stuffing the line into a std::istringstream, and reading words out of there:
std::istringstream buffer(s);
auto word_count = std::count(std::istream_iterator<std::string>(s),
std::istream_iterator<std::string());
To print out the words and their lengths as you go, you could (for example) use std::for_each instead:
int count = 0;
std::for_each(std::istream_iterator<std::string>(s),
std::istream_iterator<std::string>(),
[&](std::string const &s) {
std::cout << s << " " << s.size();
++count;});
This should not be far from you requirements - I only did minimal modification to your present code.
Limits :
you'd better use
string line;
getline(cin, line);
to read the line to be able to accept lines of any size
my present code assumes
no spaces at beginning or end of line
one single space between 2 words
it should be improved to cope with extra spaces, but I leave that to you as an exercise :-)
The code :
#include <iostream>
#include <string>
#include <cstring>
using namespace std;
int countWords(char *sentence, double& average);
int main()
{
const int size=80;
char word[size];
double average=0;
cout<<"Enter words less than " <<size-1<<" characters."<<endl;
cin.getline(word, size);
cout <<"There are "<<countWords(word, average)<<" words in the sentence."<<endl;
cout << "Average of the sentence " << average << endl;
return 0;
}
int countWords(char *sentence, double& average)
{
int words= 1;
int wordlen;
char *word = NULL;
while(*sentence != '\0')
{
if(*sentence == ' ') {
words++;
wordlen = sentence - word;
average += wordlen;
*sentence = '\0';
cout << word << " " << wordlen<< endl;
word = NULL;
}
else if (word == NULL) word = sentence;
sentence++;
}
wordlen = sentence - word;
average += wordlen;
cout << word << " " << wordlen<< endl;
average /= words;
return words;
}
For input : super great cannon boys
Output is :
Enter words less than 79 characters.
super great cannon boys
super 5
great 5
cannon 6
boys 4
There are 4 words in the sentence.
Average of the sentence 5
You can inspire here. Basically use std::getline to read from std::cin to std::string.
#include <iostream>
#include <string>
#include <cctype>
inline void printWordInfo(std::string& word) {
std::cout << "WORD: " << word << ", CHARS: " << word.length() << std::endl;
}
void printInfo(std::string& line) {
bool space = false;
int words = 0;
int chars = 0;
std::string current_word;
for(std::string::iterator it = line.begin(); it != line.end(); ++it) {
char c = *it;
if (isspace(c)) {
if (!space) {
printWordInfo(current_word);
current_word.clear();
space = true;
words++;
}
}
else {
space = false;
chars++;
current_word.push_back(c);
}
}
if (current_word.length()) {
words++;
printWordInfo(current_word);
}
if (words) {
std::cout << "AVERAGE:" << (double)chars/words << std::endl;
}
}
int main(int argc, char * argv[]) {
std::string line;
std::getline(std::cin, line);
printInfo(line);
return 0;
}
Going along the lines of what you already have:
You could define a countCharacters function, like your countWords:
int countCharacters(char *sentence)
{
int i;
char word[size];
for(i = 0; sentence[i] != ' '; i++) //iterate via index
{
word[i] = sentence[i]; //save the current word
i++;
}
cout <<word<< <<i<<endl; //print word & number of chars
return i;
}
which you can call inside your countWords function
int countWords(char *sentence)
{
int words = 1;
for(int i; sentence[i] != '\0';) //again this for loop, but without
//increasing i automatically
{
if(sentence[i] == ' ') {
i += countCharacters(sentence[++i]); //move i one forward to skip
// the space, and then move
// i with the amount of
// characters we just counted
words++;
}
else i++;
}
return words;
}