c語言編程，求絕對值的和與差。

#include <math.h>

int add(unsigned int a,unsigned int b)

{

return a+b;

}

int sub(unsigned int a,unsigned int b)

{

unsigned int t;

t=a>b?a:b;

printf("最大值是:%d\n",t);

return (t-a)==0?t-b:t-a;

}

int main(void)

{

int a,b;

printf("請輸入兩個數,如1 2:");

scanf("%d%d",&a,&b);

a=a<0?(-1)*a:a;

b=b<0?(-1)*b:b;

printf("兩數之和是%d\n",add(a,b));

printf("兩數之差是%d\n",sub(a,b));

return 0;

}