#include <iostream>
 
int main()
{
    char s[256] = "";
 
    std::cout << "input string: ";
    std::cin.getline(s, sizeof(s));
 
    size_t n = 0;
    for(char* p = s; *p != '\0'; ++p) ++n;
        std::cout << "length: " << n << std::endl;
}