how to ignore space in string in c 2b 2b

1#include <iostream>
2
3std::string IgnoreWhitespace(std::string str)
4{
5    for(int i = 0; i < str.length(); i++)
6    {
7        if(str[i] == ' ') str.erase(i, 1);
8    }
9
10    return str;
11}
12
13int main() 
14{
15    std::string str = "W h i t e s p a c e";
16
17    std::cout << IgnoreWhitespace(str); // Output = Whitespace
18
19    return 0;
20}