I'm trying to make a function that capitalizes the next character in a string after I input a "^" character. the code looks like this:
void decodeshift( string orig, string search, string replace )
{
size_t pos = 0;
while (true) {
pos = orig.find(search, pos);
if(pos == string::npos)
break;
orig.erase(pos, search.length());
orig.replace(pos, search.length(), replace);
cout<<orig<<endl;
}
}
int main()
{
string question = "What is the message? ";
string answer = "The real message is ";
string shift="^";
string test="a";
string answer1;
//output decoded message
string answer2;
cout << question;
cin >> answer1;
cout << "decoding . . . " << "\n";
//decodeback(answer1, back);
decodeshift(answer1, shift, test);
return 0;
}
my input will be:
^hello
desired output:
Hello
current output
aello
I can't seem to find the correct function to use and I'm confused on how to use toupper in a situation like this. I just need to find the proper replacement.
Try something more like this:
#include <cctype>
void decodeshift( string orig, string search )
{
size_t pos = orig.find(search);
while (pos != string::npos)
{
orig.erase(pos, search.length());
if (pos == orig.size()) break;
orig[pos] = (char) std::toupper( (int)orig[pos] );
pos = orig.find(search, pos + 1);
}
return orig;
}
...
answer1 = decodeshift(answer1, "^");
cout << answer1 << endl;
Or, simply get rid of the shift parameter:
#include <cctype>
string decodeshift( string orig )
{
size_t pos = orig.find('^');
while (pos != string::npos)
{
orig.erase(pos, 1);
if (pos == orig.size()) break;
orig[pos] = (char) std::toupper( (int)orig[pos] );
pos = orig.find('^', pos + 1);
}
return orig;
}
...
answer1 = decodeshift(answer1);
cout << answer1 << endl;
Related
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'm having difficulty creating a function that reverse the order of the sentence around. I've read many functions on how to recursively reverse the letters around and I have successfully done so, but I do not want to reverse the letters in the words. I want to reverse the placement of the words in the sentence.
Example would be:
This is a sentence.
sentence. a is This
This is my code so far. How do I go from reversing order of letters of the entire sentence to placement order of words in a sentence?
The output of the current code would provide: !dlroW olleH
void reverse(const std::string str)
{
int length = str.size();
if(length > 0)
{
reverse(str.substr(0,length-1));
std::cout << str[0];
}
}
Edit: Additional question. If this was a char array would the logic be different?
Simplify your logic by using a std::istringstream and a helper function. The program below works for me.
#include <sstream>
#include <iostream>
void reverse(std::istringstream& stream)
{
std::string word;
if ( stream >> word )
{
reverse(stream);
std::cout << word << " ";
}
}
void reverse(const std::string str)
{
std::istringstream stream(str);
reverse(stream);
std::cout << std::endl;
}
int main(int argc, char** argv)
{
reverse(argv[1]);
return 0;
}
// Pass string which comes after space
// reverse("This is a sentence.")
// reverse("is a sentence.")
// reverse("a sentence.")
// reverse("sentence.")
// will not find space
// start print only word in that function
void reverse(const std::string str)
{
int pos = str.find_first_of(" ");
if (pos == string::npos) // exit condition
{
string str1 = str.substr(0, pos);
cout << str1.c_str() << " " ;
return;
}
reverse(str.substr(pos+1));
cout << str.substr(0, pos).c_str() << " ";
}
Simple to understand:
void reverse(const std::string str)
{
int pos = str.find_first_of(" ");
if (pos != string::npos) // exit condition
{
reverse(str.substr(pos + 1));
}
cout << str.substr(0, pos).c_str() << " ";
}
std::vector<std::string> splitString(const std::string &s, char delim) {
std::stringstream ss(s);
std::string item;
std::vector<std::string> tokens;
while (getline(ss, item, delim)) {
tokens.push_back(item);
}
return tokens;
}
void reverseString(const std::string& string) {
std::vector<std::string> words = splitString(string, ' ');
auto end = words.rend();
for (auto it = words.rbegin(); it <= end; it++) {
std::cout << *it << std::endl;
}
}
reverseString("This is a sentence.");
You can split input and print them in inverse order
Or if you want to use recursive structure just move the cout after calling a function like this:
void reverse(const std::string str)
{
std::stringstream ss(str);
std::string firstWord, rest;
if(ss >> firstWord)
{
getline(ss , rest);
reverse(rest);
std::cout << firstWord << " ";
}
}
I am not a C++ programmer, but I would create another array (tempWord[ ]) to store individual word.
Scan each word and store them into tempWord array. In your case, the words are separated by space, so:
a.get the index of the next space,
b substring to the index of the next space and
c. you should get {"This", "is", "a", "sentence."}
Add them up again reversely:
a. loop index i from "tempWord.length -1" to "0"
b. new String = tempWord[i]+" ";
print out result.
I want to start of by saying that I am still learning and some might think that my code looks bad, but here it goes.
So I have this text file we can call example.txt.
A line in example.txt can look like this:
randomstuffhereitem=1234randomstuffhere
I want my program to take in the numbers that are next to the item= and I have started a bit on it using the following code.
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
string word;
int main()
{
ifstream readFile("example.txt", ios::app);
ofstream outfile("Found_Words.txt", ios::app);
bool found = false;
long int price;
cout << "Insert a number" << endl;
cout << "number:";
cin >> number;
system("cls");
outfile << "Here I start:";
while( readFile >> word )
{
if(word == "item=")
Here is the problem; first of all it only searchs for "item=" but to find it, it cannot be included with other letters. It has to be a standalone word.
It wont find:
helloitem=hello
It will find:
hello item= hello
It has to be separated with spaces which is also a problem.
Secondly I want to find numbers next to the item=. Like I want it to be able to find item=1234 and please note that 1234 can be any number like 6723.
And I dont want it to find what comes after the number, so when the number stops, it wont take in anymore data. Like item=1234hello has to be item=1234
{
cout <<"The word has been found." << endl;
outfile << word << "/" << number;
//outfile.close();
if(word == "item=")
{
outfile << ",";
}
found = true;
}
}
outfile << "finishes here" ;
outfile.close();
if( found = false){
cout <<"Not found" << endl;
}
system ("pause");
}
You can use a code like this:
bool get_price(std::string s, std::string & rest, int & value)
{
int pos = 0; //To track a position inside a string
do //loop through "item" entries in the string
{
pos = s.find("item", pos); //Get an index in the string where "item" is found
if (pos == s.npos) //No "item" in string
break;
pos += 4; //"item" length
while (pos < s.length() && s[pos] == ' ') ++pos; //Skip spaces between "item" and "="
if (pos < s.length() && s[pos] == '=') //Next char is "="
{
++pos; //Move forward one char, the "="
while (pos < s.length() && s[pos] == ' ') ++pos; //Skip spaces between "=" and digits
const char * value_place = s.c_str() + pos; //The number
if (*value_place < '0' || *value_place > '9') continue; //we have no number after =
value = atoi(value_place); //Convert as much digits to a number as possible
while (pos < s.length() && s[pos] >= '0' && s[pos] <= '9') ++pos; //skip number
rest = s.substr(pos); //Return the remainder of the string
return true; //The string matches
}
} while (1);
return false; //We did not find a match
}
Note that you should also change the way you read strings from file. You can either read to newline (std::getline) or to the end of stream, like mentioned here: stackoverflow question
Hey, sorry if this is asked a lot but I have no idea what the problem here is.
In the C++ code below, I'm reading from a user defined input file and generating output. I've been writing it piece by piece and putting it together, compiling, testing, etc as I go to work out the bugs. This is a learning experience for me, first self-directed program I guess...
Anyways, when I run the code, the command prompt prints ONE line and goes unresponsive. I would say it has been caught in some kind of loop, but I believe that's impossible.
I think it might have something to do with the array I'm trying to declare, I wanted to make a dynamic string array but I found out that's difficult...
#include <iostream>
#include <fstream>
#include <algorithm>
#include <cctype>
#include <string>
using namespace std;
int wordCount(string line)
{
int fpos, fpos2;
int count = 0;
fpos = line.find_first_not_of(' ');
line.erase(0, fpos);
while(line.size() > 0)
{
fpos = line.find_first_of(' ');
if(line.at(0) == '"')
{
line.erase(0, 1);
for(int i = 0; i <line.size(); i++)
if(line.at(i) == '"' && line.at(i-1) != '\\')
{
fpos2 = i;
break;
}
line.erase(0, fpos2 + 2);
}
else
line.erase(0, fpos + 1);
count++;
}
return count;
}
int main()
{
//Current line; Input file; Output file;
string currentline, fileName, outFileName;
ifstream fin;
ofstream fout;
cout << "Enter input file name: ";
getline(cin, fileName);
cout << "Enter output file name: ";
getline(cin, outFileName);
fin.open(fileName.c_str());
if (!fin.good()) throw "I/O error";
fout.open(outFileName.c_str());
if (!fout.good()) throw "I/O error";
getline(fin, currentline);
while (!currentline.empty())
{
int pos, pos1;
pos = currentline.find("//");
string postScript = currentline.substr(pos+2,-1);
pos = currentline.find_first_of(';');
string xline = currentline.substr(0,pos+1);
cout << xline << endl;
int size = wordCount(xline);
string *words;
words = (string *) malloc (size*sizeof(string));
words = new string[size];
pos = xline.find_first_not_of(' ');
xline.erase(0, pos);
for ( int i = 0; i < size; i++ )
{
pos = xline.find_first_of(' ');
if ( xline.at(0) == '"' )
{
xline.erase(0, 1);
for(int a = 0; a < xline.size(); a++) //This for loop finds the end of a quoted statement within the line.
if ( xline.at(a) == '"' && xline.at(a-1) != '\\' )
{
pos = a;
break;
}
words[i] = xline.substr(0,pos);
xline.erase(0,pos + 2);
}
else
{
words[i] = xline.substr(0,pos);
xline.erase(0,pos + 1);
}
cout << words[i] << endl;
}
cout << xline << endl << endl;
getline(fin, currentline);
}
return 0;
}
I would suggest you commenting out bits of code until it starts to work the way you expect (Usually the problematic bit will become obvious this way.) Once you figure out what is wrong you can ask a more specific question on StackOverflow.
You should use a debugger to investigate the program behavior.
To avoid single stepping the whole program, you can set breakpoints where you expect to passs the sequence. When a breakpoint is not hit you can use single stepping from the previous point. Additionally you can look at variables content.
It never finds the end quote:
if ( xline.at(a) == '"' && xline.at(a-1) != '\\' )
{
pos = a;
break;
}
Try this instead:
if (xline.at(a) == '"')
{
pos = a;
break;
}
You only need to escape " if its contained in a string literal, e.g. "There's a \" in this literal"