implicit declaration of function `initgraph'小白请教一下各位大神，这个警告该如何解决
#include<stdio.h>#include<graphics.h>
int main()
{
initgraph(640,480);
int r=0;
int s=5;
while(1)
{
circle(320, 240, r+=5);
if(r>200||r<10)
{
s=-s;
}
sleep(50);
}
return 0;
}
