giveMeFive.cpp

#include <iostream>

int giveMeFive(const int& a, const int& b)
{
    
    int containsFive = 0;
    
    for (int i = a; i <= b; ++i) {
        std::string number = std::to_string(i);
        
        for (auto ch : number) {
            if (ch == '5') {
                ++containsFive;
                break;
            }
            
        }
    }
    return (b-a)-containsFive + 1;
}

int main()
{
    std::cout << giveMeFive(-10, 0) << std::endl;
}