C++ remove whitespace

Question

I have this code to remove whitespace in a std::string and it removes all characters after the space. So if I have "abc def" it only returns "abc". How do I get it to go from "abc def ghi" to "abcdefghi"?

#include<iostream>
#include<algorithm>
#include<string>

int main(int argc, char* argv[]) {
    std::string input, output;
    std::getline(std::cin, input);

    for(int i = 0; i < input.length(); i++) {
        if(input[i] == ' ') {
            continue;
        } else {
            output += input[i];
        }
    }
    std::cout << output;
    std::cin.ignore();
}

Solution 1

The issue is that cin >> input only reads until the first space. Use getline() instead. (Thanks, @BenjaminLindley!)

Solution 2

Well the actual problem you had was mentioned by others regarding the cin >> But you can use the below code for removing the white spaces from the string:

str.erase(remove(str.begin(),str.end(),' '),str.end());

Solution 3

Since the >> operator skips whitespace anyway, you can do something like:

while (std::cin>>input)
    std::cout << input;

This, however, will copy the entire file (with whitespace removed) rather than just one line.

Solution 4

My function for removing a character is called "conv":

#include <cstdlib>
#include <iostream>
#include <string>

using namespace std;

string conv(string first, char chr)
{
    string ret,s="x";
    for (int i=0;i<first.length();i++)
    {
        if (first[i]!=chr)
        s=s+first[i]; 
    }
    first=s;
    first.erase(0,1);
    ret=first;
    return ret;
    }
int main()
{
    string two,casper="testestestest";
    const char x='t';
    cout<<conv(casper,x);
    system("PAUSE");
    return 0;
}

You need to change the const char x to ' ' (whitespace, blanco) for the job to be done. Hope this helps.

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Comments

[Benjamin Lindley]

You mean the getline free function, since it's better, and input is a std::string anyway.

[BruceAdi]

As @BenjaminLindley mentioned, use istream& getline ( istream& is, string& str, char delim ); istream& getline ( istream& is, string& str );

[user2007447]

please use english in your code... This is why C++ keywords are in english, to be globally understood...

[Aleksandar]

@user2007447 that was truly an onld

[Adrian McCarthy]

That's for removing the spaces from the string in-place. If you want a copy without the spaces (as in the OP), you can use std::copy_if(input.begin(), input.end(), std::back_inserter(output), [](char ch) { return ch != ' '; });.