// intro to malloc
#include <stdlib.h>
main(int argc, char *argv[]) {
	int i, n, *ip;
	unsigned char *cp;
	if(argc > 1)
		n = atoi(argv[1]);
	else
		n = 1000000;

	// datatypes have sizes
	printf("sizeof int is %d\n", sizeof(int));
	printf("sizeof char is %d\n", sizeof(char));
	printf("sizeof unsigned char is %d\n", sizeof(unsigned char));

	// we can dynamically allocate space using malloc(nbytes);
	ip = malloc(n * sizeof(int));
	cp = malloc(n);		// we "know" char is always just 1 byte

	// we can access the space using pointer notation
	for(i = 0; i < n; i++) {
		*(ip + i) = i;
		*(cp + i) = i;
	}
	// or, we more commonly use array notation to do the same thing
	for(i = 0; i < n; i++) {
		ip[i] = i;
		cp[i] = i;
	}

	printf("ip[50000] is %d\n", ip[50000]);
	// why is this one different?
	printf("cp[50000] is %d\n", cp[50000]);
}