java - 二次方程因子计算

Question

关于二次方程(了解更多 here )，我将方程的 a、b 和 c 视为输入。

示例方程如下:21x^2 - 8x - 4 这里，a = 21，b = -8，c = -4。所以，在求解时(没有公式)， => 21x^2 - 14x + 6x - 4 = 0。

我需要中间的两个数字，即本例中的 14 和 6(读取因子)。我想我都做对了，但是输入似乎是无限的，根本不会停止。你能纠正这个错误吗？我也很好奇为什么会发生这种情况。

import java.util.Scanner;
public class QuadFact {
    static Scanner sc = new Scanner(System.in); 
    static int a,b,c; 
    static int P, diff, p; 
    static int i;
    static boolean found = false;

    void accept(){
        System.out.println("Enter the a, b, c");
        a = sc.nextInt(); b = sc.nextInt(); c = sc.nextInt();
    }

    void compute(){
        P = a * c;
        diff = 0;
        while(!found){
           for (i = b + 1;;i++){
                diff = i - b;
                p = i * diff;
                if (p==P) {
                    found = true;
                    break; 
                }
            }
        }
    }

    void display(){
        System.out.print("These are the raw numbers, should be   correct.  
        Still,\n it is advisable you verify it.");
        System.out.println("One factor: " + i);
        System.out.println("Other factor: " + diff);
    }

    public static void main(String[] args){
        QuadFact a = new QuadFact();
        a.accept();
        a.compute();
        a.display();
    }
}

Answer 1

我认为你必须在 b 的“两侧”寻找加起来为 b 并产生乘积 a*c 的因子对。

void compute(){
    P = a * c;
    while(!found){
    for( i = 1; ; i++ ){
            diff = b - i;
            if (i * diff == P) {
                found = true;
                break; 
            }
            diff = b + i;
            if (-i * diff == P) {
                found = true;
                break; 
            }
        }
    }
}