qsortFunc.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>


int compare_scores(const void* score_a, const void* score_b){
	int a =*(int*)score_a;
	int b =*(int*)score_b;
	return a-b;
}

int compare_scores_desc(const void* score_a, const void* score_b){
	int a = *(int*)score_a;
	int b =*(int*)score_b;
	return b-a;
}

typedef struct{
	int width;
	int height;
}rectangle;

int compare_areas(const void* a, const void* b){
	rectangle* area1 = (rectangle*)a;
	rectangle* area2 = (rectangle*)b;
	
	int area_a = (area1->width * area1->height);
	int area_b = (area2->width * area2->height);
	
	return area_a - area_b;
	 
	//return sizeof(area1)-sizeof(area2);
}

int compare_names(const void* a,const void* b){
	char** name1 = (char**)a;
	char** name2 = (char**)b;
	
	return strcmp(*name1,*name2);
}

int compare_areas_desc(const void* a, const void* b){
	return compare_areas(b,a);
}

int compare_names_desc(const void* a,const void* b){
	return compare_names(b,a);
}
	
int main(){
	int scores[]={543,323,32,554,11,3,112};
	int i;
	qsort(scores,7,sizeof(int),compare_scores_desc);
	puts("These are the scores in order:");
	for(i=0;i<7;i++){
		printf("Score = %i\n",scores[i]);
	}
	
	char* names[]={"Karen","Mark","Brett","Molly"};
	qsort(names,4,sizeof(char*),compare_names);
	puts("These are the names in order:");
	for(i = 0; i<4;i++){
		printf("%s\n",names[i]);
	}
	
	return 0;

}