1	#include <stdio.h>
     2	#include <stdlib.h>
     3
     4	void CalcChangeFor(int pence)
     5	{
     6	int i, j, val;
     7	int coins[] = { 500,200,100,50,20,10,5,2,1,};
     8
     9		if (pence == 0)
    10			return;	/* amount is exact */
    11		if (pence < 0)
    12			return;	/* invalid amount */
    13
    14		for(i=0;i<sizeof(coins)/sizeof(coins[0]);i++) {	/* for each coin */
    15			val = coins[i];
    16			for(j=pence;j>0;j--)
    17				if (val*j <= pence) {
    18					printf("%d x %dp\n", j, val);
    19					CalcChangeFor(pence - j*val);
    20					return;
    21					}
    22			}
    23	}
    24	
    25	void usage(void)
    26	{
    27		fprintf(stderr, "Usage: change <amount>\n");
    28	}
    29
    30	int main(int argc, char **argv)
    31	{
    32		if (argc > 1)
    33			CalcChangeFor(atoi(argv[1]));
    34		else
    35			usage();
    36		return 0;
    37	}