我是编码方面的新手,我不太确定如何100%写出这个问题。我试图弄清楚为什么我的程序只存储值“ a”的第一个输入,即使该数字为负数也是如此。

例如:a = -1(值必须大于0。再次输入值'a':) a = 1 b = 3 c = -4

因此,在程序编译时,仅存储了“ a”(-1)的第一个值,而不存储第二个值(1),并且在遇到第二个if代码块时终止了程序。我完全不知道如何解决这个问题:/

这是我的代码:

package quadratic;

import java.util.*;

//Program that does quadratic equations
public class Quadratic{
    public static void main(String[] args){

        boolean run = true;
        while(run){ //if program completes true, will start program again
            Scanner sc = new Scanner(System.in); // set scanner to allow user input

            System.out.println("Please enter value for 'a':");
            double a = (sc.nextDouble()); //looking for user input
            if (a <= 0){
                System.out.print("Value must be greater than 0. Enter value 'a' again:\n");
                sc.nextDouble(); //prompt user again if value less than or equal to 0
            }
            System.out.println("Please enter value for 'b':");
            double b = (sc.nextDouble());
            System.out.println("Please enter value for 'c':");
            double c = (sc.nextDouble());
            System.out.printf("Values entered: a:%s b:%s c:%s \n",a,b,c);

            if (Math.pow(b,2)- (4 * a * c) <= 0){
                System.out.println("Impossible. Program Terminating");
                System.exit(0); //Terminate program
            }

            double qf1 = (-b + Math.sqrt(Math.pow(b, 2) - (4 * a * c))) / (2 * a);
            double qf2 = (-b - Math.sqrt(Math.pow(b, 2) -(4 * a * c)))/ (2 * a);
            // qf stands for Quadratic Formula
            System.out.printf("Anwser One: %s \n", qf1); //%s whatever qf1 returned
            System.out.printf("Anwser Two: %s \n", qf2); //%s whatever qf2 returned
        }
    }
}

最佳答案

你只是打电话

sc.nextDouble(); //prompt user again if value less than or equal to 0




a = sc.nextDouble(); //prompt user again if value less than or equal to 0


所以,您只是丢掉第二个数字

此外,您可以第二次输入一个负数,因为您无需检查该数字是否小于零(提示:可能是一个循环,直到输入a的有效值?)

关于java - 带有用户输入的二次公式(Java),我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/31279637/

10-11 22:49
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