C语言指针开辟内存释放内存

#include "stdio.h"
#include "string.h"
#include "stdlib.h"
int main(){
char *a=NULL;
char *b=NULL;
a=(char*)malloc(100);
b=(char*)malloc(100);
a="abc";
b="abc";
int result=strcmp(a,b);
printf("result is %d.\n",result);
free(a);
free(b);
}