CODEWITHSUNDEEP
c++string
Kc North
Kc North

Reputation: 31

Double space after period remover

People who learned how to type before word processors often add two spaces after a period ending a sentence. Write a function singleSpaces that accepts a string and returns that string with all occurrences of two spaces after a "." into changed single spaces.)

This is what I have; what am I doing wrong?

#include <cmath>
#include <iostream>
using namespace std;



string forceSingleSpaces1 (string s) {
    string r = "";
    int i = 0;
    while (i < static_cast <int> (s.length()))  {
        if (s.at(i) != ' ')  {
            r = r + s.at(i);
            i++;
        } else  {
            r +=  ' ';
            while (i < static_cast <int> (s.length()) && s.at(i) == ' ')
                i++;
        }
    }
    return r;
}

Upvotes: 1

Views: 778

Answers (3)

epidemian
epidemian

Reputation: 19229

You might (re)use a more general function that replaces occurrences of a given string within a string with another string, as described here.

#include <string>
#include <iostream>

void replace_all(std::string& str, const std::string& from, const std::string& to) {
    size_t start_pos = 0;
    while((start_pos = str.find(from, start_pos)) != std::string::npos) {
        str.replace(start_pos, from.length(), to);
        start_pos += to.length(); // In case 'to' contains 'from', like replacing 'x' with 'yx'
    }
}

int main() {
    std::string text = "I'm old.  And I use two spaces.  After periods.";
    std::string newstyle_text(text);
    replace_all(newstyle_text, ".  ", ". ");
    std::cout << newstyle_text << "\n";

    return 0;
}

Update

If you are not afraid of being on the cutting edge, you might consider using TR1 regular expressions. Something like this should work:

#include <string>
#include <regex>
#include <iostream>

int main() {
    std::string text = "I'm old.  And I use two spaces.  After periods.";
    std::regex regex = ".  ";
    std::string replacement = ". ";
    std::string newstyle_text = std::regex_replace(text, regex, repacement);

    std::cout << newstyle_text << "\n";

    return 0;
}

Upvotes: 2

marcinj
marcinj

Reputation: 50016

In your assignment there is talk about double spaces after dot, and not all double spaces in text. So you should modify your code so that it

  • waits for a '.'and not ' ',
  • when '.' is intercepted then add it, after that add any single space

you can think of this code as two states machine:

state 1 - is when you are looping on any non '.' character, in this state your code adds to result all what it finds

state 2 - is when '.' is found, and in this state you use different code, you add '.' to results and ater that exactly single space (if any one was found)

this way you have your problem divided into two sub problems

[edit] - replaced source code with modification hints

Upvotes: 2

Trevor Hickey
Trevor Hickey

Reputation: 37894

#include <iostream>
#include <string>
#include <cstdlib>
using namespace std;

//1. loop through the string looking for ".  "
//2. when ".  " is found, delete one of the spaces
//3. Repeat process until ".  " is not found.  

string forceSingleSpaces1 (string str) {
    size_t found(str.find(".  "));
    while (found !=string::npos){
        str.erase(found+1,1);
        found = str.find(".  ");
    }

    return str;
}

int main(){

    cout << forceSingleSpaces1("sentence1.  sentence2.  end.  ") << endl;

    return EXIT_SUCCESS;
}

Upvotes: 0

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