>>524
#include<stdio.h>
double f(double x)
{
double y;
y=(((3.1*x-1.8)*x+5.7)*x+1.0)*x-6.2;
return (y);
}
main()
{
double x,y,y_sum=0;
int i;
for(i=-20;i<=20;i++){
x=0.5*i;
y_sum+=y=f(x);
printf("x=%7.3f y=%12.3f\n",x,y);
}
printf("y_sum=%12.3f\n",y_sum);
}