親，我們這邊建議您看一下函數main前面的類型，希望能對您有幫助，可以的話給個五星好評呢!

#include?<stdio.h>
int?main()
{
?????float?x,y;
?????printf("x+y=%f\n",x+y);
?????printf("x-y=%f\n",x-y);
?????printf("x*y=%f\n",x*y);
?????printf("x/y=%f\n",x/y);
?????printf("x%%y=%f\n",x%y）;
?????return0;
??}