这段程序哪里错了？小白求教

Question

#include
#include
main()
{
int i;
float a;
float b;
b=28;
for (i=0;i<=99;i++);
a=b-(sqrt(783)／100);
b=a;
printf("f%",b);
}

Answer 1

／，这是全角
printf("f%",b);
是%f