题解 | #牛牛学梯形#
牛牛学梯形
https://ac.nowcoder.com/acm/problem/21995
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main()
{
int up,down,height;
float s;
scanf("%d %d %d",&up,&down,&height);
s=(up+down)*height/2.0;
printf("%.3f",s);
return 0;
} 
