Question

void reverse (char s[]){
int len = strlen(s);
int j = len - 1;
for (int i = 0; i < j; i++,j--){
    cout << s[i];
    char ch = s[i];
    s[i] = s[j]; //error line - giving exception, cannot write to the memory
    s[j] = ch;
    }
}

I am using Visual Studion 2008 and i can’t understand whats the problem here .. :s .. I am out of C++ practice :$ .

Answer 1

The problem is that it uses C-style strings instead of C++ style strings. In particular, you are apparently trying to write to a constant string literal:

char const* str = "I cannot be written to";

C++ allows to omit the const here for backwards compatibility but the literal is still constant.

Finally, C++ already has a reverse function:

#include <algorithm>
#include <iostream>
#include <string>

int main() {
    std::string str = "Hello world";
    std::reverse(str.begin(), str.end());
    std::cout << str << std::endl;
}