/**
 * Program to show hexadecimal representation of ints and doubles.
 *
 * Attempts to be as portable as possible by copying data to an
 * array of characters (bytes) and printing representations of bytes.
 *
 * Also prints sizes of some things (to show how they can be different
 * on different systems).
 */
#include <stdio.h>
#include <string.h>

/*
 * print hexadecimal representation of array of chars
 * "size_t" here is an unsigned integer type big enough to hold sizes
 * of things.
 */
void print_chars_hex(char* chars, size_t num_chars) {
    for (size_t i = 0; i < num_chars; ++i) {
        printf("%.2hhx ", chars[i]);
    }
    printf("\n");
}

/* 
 * print hexadecimal representation of int:
 * copy to array of characters and use print_chars_hex
 */
void print_int_hex(int n) {
    char chars[sizeof n];
    memcpy(chars, &n, sizeof n);
    printf("int %d in hexadecimal is ", n);
    print_chars_hex(chars, sizeof chars);
}

/* 
 * print hexadecimal representation of double:
 * copy to array of characters and use print_chars_hex
 */
void print_double_hex(double d) {
    char chars[sizeof d];
    memcpy(chars, &d, sizeof d);
    printf("double %g in hexadecimal is ", d);
    print_chars_hex(chars, sizeof chars);
}

/* main program */
int main(void) {

    double d;

    printf("sizeof int is %zd\n", sizeof(int));
    printf("sizeof short is %zd\n", sizeof(short));
    printf("sizeof long is %zd\n", sizeof(long));
    printf("sizeof size_t is %zd\n", sizeof(size_t));
    printf("sizeof float is %zd\n", sizeof(float));
    printf("sizeof double is %zd\n", sizeof(double));
    printf("\n");

    printf("enter floating-point values, anything else to end:\n");
    while (scanf("%lg", &d) == 1) {
        print_int_hex((int) d);
        print_double_hex(d);
    }
    return 0;
}