#include <stdio.h> int main () { int f; int x=0; printf("请输入x的值\n"); scanf("%d",&x); printf("您输入的x值为%d\n",x); if (x<0){ f=-1; printf("f=%d",f); } else if(x==0){ f=0; printf("f=%d",f); } else{ f=1; printf("f=%d",f); } return 0; }