Frequency of a character in string in C++

#include <iostream>
using namespace std;
int main()
{
    string str="C++ Programming is awesome";
    char checkCharacter='a';
    int count=0;
    for (int i=0;i<str.size();i++)
    {
        if (str[i]==checkCharacter)
        {
            ++count;
        }
    }
    cout<<"Number of "<<checkCharacter<<" = "<<count;
}