C - counting the number of times a char appears in a string

Code: https://gist.github.com/3394648

	#include <stdio.h>
	#include <string.h>
	#include <stdlib.h>
	int** count_chars(char *s)
	{
	int **counts = (int**)malloc(256 * sizeof(int) * sizeof(char));
	int i;
	for(i = 0; i < 256; i++)
	{
	counts[i] = (int*)malloc(sizeof(int)*2);
	counts[i][0] = i;
	counts[i][1] = 0;
	}
	while(*s)
	{
	counts[(int)*s][1] += 1;
	s++;
	}
	return counts;
	}
	int int_pair_asc(const void *a, const void *b){
	int *first = *(int**)a;
	int *second = *(int**)b;
	return first[1] - second[1];
	}
	int int_pair_desc(const void *a, const void *b){
	return (int_pair_asc(a, b) * -1);
	}
	int main(){
	char msg[] = "I am a large brown bear who lives in the forest. My diet consists primarily of honey and spaceships.";
	printf("string: '%s'\n", msg);
	int **counts = count_chars(msg);
	qsort(counts, 256, sizeof(int), int_pair_desc);
	int i;
	for(i = 0; i < 256; i++){
	if(counts[i][1] > 0)
	printf("Rank[%d]: '%c' - %d\n", i+1, counts[i][0], counts[i][1]);
	}
	return 0;
	}

view raw countchars.c hosted with ❤ by GitHub

This was a nice exercise that helped me get more familiar with malloc and pointers.  I was really happy when I got the two dimensional array pointers working on the first try!