清华大学出版社 TSINGHUA UNIVERSITY PRESS 有以下几个程序,请读者判断哪个是正确的? 程序1: main() {int x,y; scanf("%d",&x); ifx<0)y=-1; else if(x=-0)y=0; else y=1; printf("x=%d,y=%dn",x,y);有以下几个程序,请读者判断哪个是正确的? 程序1: main() {int x,y; scanf("%d",&x); if(x<0)y=-1; else if(x==0) y=0; else y=1; printf("x=%d,y=%d\n",x,y); }