PAT 03-树1. 二分法求多项式单根(20)

没有用Tree...

#include <stdlib.h>#include <stdio.h>float Calculate(float a3, float a2, float a1, float a0, float x){float result;result = a3*x*x*x + a2*x*x + a1*x + a0;return result;}int main(){float a3, a2, a1, a0;float a, b;scanf("%f %f %f %f", &a3, &a2, &a1, &a0);scanf("%f %f", &a, &b);while (b-a>0.01){float r = Calculate(a3, a2, a1, a0, (a+b)/2);float ra = Calculate(a3, a2, a1, a0, a);float rb = Calculate(a3, a2, a1, a0, b);if (r==0)break;else{if (r*ra < 0){b = (a+b)/2;}else{a = (a + b) / 2;}}}printf("%.2f",(a+b)/2);}