String not being printed by C++

Question

Sorry for the noob question, I\'m a newbie programmer and transitioning from C to C++. I could easily write a program to reverse a string in C the same way with minor change

Answer 1

To fix your string reverse code you just have to resize the string object p:

int main(){
    std::string s = "hello",
           p;
    p.resize(s.size()); // this was causing your problems, p thought it was size 0

    for (int i = s.size() - 1, j = 0; i >= 0; i--, j++)
    {
        p[j] = s[i];
    }

    std::cout << p << std::endl;
    return 0;
}

In addition to this, there is no need to find \0 in the string, while it will be there, you can just ask std::string what its size() is.

On a side note, while std::string probably allocates some memory by default, just assuming it has enough to store whatever you input is going to be undefined behaviour.