一元三次方程用弦截法求解，出现这样的报警解决方法

一元三次方程用弦截法求解，出现这样的报警
#include<stdio.h>
#include<math.h>
float f(float x)
{
float y;
y=((x-5.0)*x+16.0)*x-80.0;
return(y);
}
float xpoint(float x1,float x2)
{
float y;
y=(x1*f(x2)-x2*f(x1))/(f(x2)-f(x1));
return(y);
}
float root(float x1,float x2)
{
float x,y,y1;
y1=f(x1);
do
{
x=xpoint(x1,x2);
y=f(x);
if(y*y1>0)
{
y1=y;
x1=x;
}
else
x2=x;
}
while(fabs(y)>=0.0001);
return(x);
}
void main()
{
float x1,x2,f1,f2,x;
do
{
printf("input x1,x2:\n");
scanf("%f,%f",&x1,&x2);
f1=f(x1);
f2=f(x2);
}
while(f1*f2>=0);
x=root(x1,x2);
printf("A root of equantion is %8.4\n",x);
}
LIBCD.lib(wincrt0.obj) : error LNK2001: unresolved external symbol _WinMain@16
Debug/9531.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.这2个是什么报警，到底那里出错了

------解决方案--------------------
估计是你的编译软件的问题
我用TURBO C编译了一下,一点问题都没有