#include <cstddef>
#include <iostream>

// Try running this code with various inputs.
// Is it working correctly, or is there a bug?
//
// Once you get it working, try entering the
// strings
//
//     HI
//
// and
//
//     Hi!
//
//   - What are their lengths?
//   - Why?

// Function declarations
std::size_t length( char const str[] );
int main();

// Function definitions
int main() {
    char str[1000];

    for ( std::size_t n{ 0 }; n < 4; ++n ) {
        // std::cin reads characters up to the first
        // whitespace character, such as a space (' '),
        // newline ('\n'), or tab ('\t').
        std::cout << "Enter a string: ";
        std::cin  >> str;

        std::cout << "The string you entered was \""
                  << str << "\"." << std::endl;

        std::cout << "The length of your string is "
                  << length( str ) << "." << std::endl;
    }

    return 0;
}

// Calculate the length of a string.
std::size_t length( char const str[] ) {
    std::size_t len{ 0 };

    while ( str[len] != '0' ) {
        ++len;
    }

    return len;
}















// The bug is in the comparison.
//
// The character '0' is the digit zero. It is an
// ordinary character that could appear in a string
// such as
//
//     "ECE150"
//
// In ASCII, the character '0' is represented by
//
//     00110000
//
// while '1' is represented by
//
//     00110001
//
// and '2' by
//
//     00110010
//
// and so on.
//
// A C-style string, however, ends with the null
// character '\0'. In ASCII, the null character is
//
//     00000000
//
// Thus, the loop should be
//
//     while ( str[len] != '\0' ) {
//         ++len;
//     }
//
// For example, the string
//
//     "Hi!"
//
// is stored as four characters:
//
//     'H'  'i'  '!'  '\0'
//
// Its length is 3 because the null character marks
// the end of the string and is not part of its length.




























// Here is the corrected function:

/*
std::size_t length( char const str[] ) {
    std::size_t len{ 0 };

    while ( str[len] != '\0' ) {
        ++len;
    }

    return len;
}
*/