Came from CSAPP “Figure 2.4”

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#include <stdio.h>

typedef unsigned char *byte_pointer;

void show_bytes(byte_pointer start, size_t len) {
	int i;
	for (i = 0; i < len; i++)
		printf(" %.2x", start[i]);
	printf("\n");
}

void show_int(int x) {
	show_bytes((byte_pointer) &x, sizeof(int));
}

void show_float(float x) {
	show_bytes((byte_pointer) &x, sizeof(float));
}

void show_pointer(void *x) {
	show_bytes((byte_pointer) &x, sizeof(void *));
}

• After typedef unsigned char *byte_pointer;, the type byte_pointer has the same functionality of unsigned char *
• % starts the format, .2 means minimum 2 digits, pad with zeros if needed.
• start[i] = *(start + i) = $*(start + i \cdot sizeof(byte_pointer)$.
• The expression &x creates a pointer to the location holding the object indicated by variable x.
• The cast (byte_pointer) &x indicates that whatever type the pointer &x had before, the program will now reference a pointer to data of type unsigned char. The casts do not change the actual pointer; they simply direct the comiler to refer to tha data being pointed to according to the new data type.