How would I use the following in c++...int searchChar(char, string)

Question

I have a function definition

int searchChar(char, string)
{/* ... */}

I do not know how to use it. I have to return the number of times a char appears in a string. I thought that we are suppose to use char and string with a variable. I do not know how to use it in this way.

Answer 1

#include <iostream>
#include <string>

int searchChar(char /*toFind*/, std::string /*str*/);

int main()
{
    std::string s = "hello world";
    std::cout << searchChar('l', s); // displays '3'
    return 0;
}

int searchChar(char toFind, std::string str)
{
    int count = 0;
    for(size_t i = 0; i < str.length(); ++i)
    {
        if (str[i] == toFind)
            ++count;
    }
    return count;
}

/*
Alternatively:

int searchChar(char toFind, std::string str)
{
    int count = 0;
    for(std::string::iterator iter = str.begin(); iter != str.end(); ++iter)
    {
        if (*iter == toFind)
            ++count;
    }
    return count;
}
*/

/*
Alternatively:

int searchChar(char toFind, std::string str)
{
    int count = 0;
    for(char ch : str)
    {
        if (ch == toFind)
            ++count;
    }
    return count;
}
*/

/*
Alternatively:

#include <algorithm>

int searchChar(char toFind, std::string str)
{
    return std::count(str.begin(), str.end(), toFind);
}
*/