[C++] Why use the STL? A quick example

[wtd]

So, let's say you want to remove all bad characters (to be defined) from a string. First we'll look at the problem solved without the STL, then taking advantage of it.

For both examples we'll want a function which can test to see if a character matches what we'll consider a "bad" character.

code:

bool bad_char(char source) {    // return true if the character is the letter o.    return (source == 'o'); }

Now, without the STL:

code:

#include <string> #include <sstream> #include <iostream> bool bad_char(char source) {    // return true if the character is the letter o.    return (source == 'o'); } int main() {    std::string original_string = "Hello world";    std::stringstream new_string_buffer;    for (int i = 0; i < original_string.length(); i++)    {       if (!bad_char(original_string[i]))       {                   new_string_buffer << original_string[i];           }    }    std::string new_string = new_string_buffer.str();    std::cout << "original: " << original_string << std::endl              << "new:      " << new_string      << std::endl; }

And with the STL:

code:

#include <string> #include <algorithm> #include <iostream> bool bad_char(char source) {    // return true if the character is the letter o.    return (source == 'o'); } int main() {         std::string original_string = "Hello world!", new_string;         std::remove_copy_if(original_string.begin(),                             original_string.end(),                             std::back_inserter(new_string),                             bad_char);     std::cout << "original: " << original_string << std::endl               << "new:      " << new_string      << std::endl; }