ax2+bx+c＝0与x轴围成的面积，怎么用C＋＋编写？要求由流程图，谢谢！

#include <iostream>
#include <cmath>
using namespace std;

#define ERROR 0
#define OK 1

int solve(double a,double b,double c,double &x1,double &x2)
{
    double delta=b*b-4*a*c;
    if(delta<0)return ERROR;
    x1=(-b-sqrt(delta))/(2*a);
    x2=(-b+sqrt(delta))/(2*a);
    return OK;
}

double area(double a,double b,double c,double x1,double x2)
{
    return fabs(a/3*(x2*x2*x2-x1*x1*x1)+b/2*(x2*x2-x1*x1)+c*(x2-x1));
}

int main()
{
    double a,b,c,x1,x2;
    scanf(\"%lf %lf %lf\",&a,&b,&c);
    if(solve(a,b,c,x1,x2)==OK)
        printf(\"%lf\n\",area(a,b,c,x1,x2));
    else {
        printf(\"0\n\");
    }
}