题目链接http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=24&page=show_problem&problem=1012
不解释
#include"stdio.h" int main() { int v,t; while(scanf("%d %d", &v,&t) != EOF) printf("%d\n", 2*v*t); return 0; }