Question

I’m making a console calculator, and I want to remove any whitespace that the user might enter while using the program. This is the code:

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

using namespace std;

int main()
{
    string str;
    std::cout<<"Enter sum): ";
    cin>>str;
     str.erase(std::remove_if(str.begin(), str.end(), (int(*)(int))isspace), str.end());
    cout<<str;
    system("pause");
    return 0;
}

if i entered 2 + 2 =, output should be 2+2=
but the output is: 2
am i using the wrong function here?

Answer 1

Your use of remove_if and erase is fine. Your method for getting input is not. operator>> is whitespace delimited. Use getline instead.

int main()
{
    string str;
    std::cout<<"Enter sum): ";
    getline(cin,str);
    str.erase(std::remove_if(str.begin(), str.end(), (int(*)(int))isspace), str.end());
    cout<<str;    
    return 0;
}