Please help explaining this code

[Ch1156]

I have some code here that someone else on this site wrote for me, and i was wondering some things about it.

CODE:

#include <iostream>
#include <string>

using namespace std;

int main()
{
    string input;

    getline (cin, input);

    string wordToFind("shit");
    string newWord ("****");

    size_t pos;

    pos = input.find(wordToFind);

    if (pos == string::npos)
    {
        cout << "" << endl;

    }
    else
    {

        input.replace(input.begin()+ pos + wordToFind.size(), newWord) ;
        cout << input << endl;
    }


}

Ok so my first question is what does .begin() do?? I watched a tutorial that covered .find, .replace and .erase but not .begin. Please just give me a plain english answer like, it does this, Please dont give me a technical answer like this: size_t is basically an unsigned integer. It's a typedef. Ok, but what does it do? and that is also my question, what is size_t?

Also this entire line is a bit confusing:

input.replace(input.begin()+ pos + wordToFind.size(), newWord) ;

In general having the entire thing explained would help me immensly. Thanks for the help. :)

[Moschops]

what does .begin() do??

The string function begin returns an iterator object that refers to the first character in the string.
http://www.cplusplus.com/reference/string/string/begin/

[Albatross]

size_t is an integer that goes from 0 to at least the largest number of bytes your computer can hold. On a 32-bit computer, this value may be ~4 billion.

-Albatross

[ne555]

input.replace(input.begin()+ pos + wordToFind.size(), newWord); does not compile.
Check out the correct version http://cplusplus.com/reference/string/string/replace/

In pos you've got the index of the first ocurrence of the substring.

[guestgulkan]

@ch1156
Mate, If you are going to repeat what someone wrote, then at least get it right


This is what I wrote...

 string input;

    getline (cin, input);

    string wordToFind("shit");
    string newWord ("crap");
    
    size_t pos;

    pos = input.find(wordToFind);

    if (pos == string::npos)
    {
        cout << "** Error - Search string not found in input **" << endl;

    }
    else
    {

        input.replace(input.begin()+pos, input.begin()+ pos+ wordToFind.size(), newWord) ;
        cout << input << endl;
    }

[ne555]

You could just input.replace(pos, wordToFind.size(), newWord);