java - 打印结果表时出现问题

Question

我试图让它在每次时间为整数(ei、2.0、4.0、12.0 等)时打印结果列表，但它只打印结果的第一行。 if条件错误吗？或者我的打印值的命令？

包a03;

导入java.util.Scanner;

/** * * @author Calvin (A00391077) 该程序模拟大炮在预设位置开火 * 由用户设置。 */公开课大炮{

public static final double DELTA_T = 0.001;
public static final double GRAVITY = 9.81;

/**
 * @param args the command line arguments
 */
public static void main(String[] args) {

    //variables
    Scanner kbd = new Scanner(System.in);
    double muzzleVelocity, muzzleHeight, time, height, velocity;

    //introducing program
    System.out.println("Cannon Simulation");
    System.out.println("-----------------");
    System.out.println();
    System.out.println("This program simulates firing a cannon straight"
            + "up into the air. Velocity");
    System.out.println("is measured in metres per second squared and"
            + " height in meteres.");
    System.out.println();
    System.out.println("By Calvin Elliott (A00391077");
    System.out.println();
    System.out.println("...press enter...");
    kbd.nextLine();
    System.out.println();

    //getting muzzle velocity
    System.out.println("What is the muzzle velocity of the projectile?");
    muzzleVelocity = kbd.nextDouble();

    while (muzzleVelocity <= 0) {
        System.out.println("The velocity must be positive");
        System.out.println("What is the muzzle velocity of the projectile?");
        muzzleVelocity = kbd.nextDouble();
    }

    //getting muzzle height
    System.out.println("what height is the muzzle above the ground?");
    muzzleHeight = kbd.nextDouble();

    while (muzzleHeight <= 0) {
        System.out.println("The position must be positive");
        System.out.println("What height is the muzzle above the ground?");
        muzzleHeight = kbd.nextDouble();

    }

    //calculations
    height = muzzleHeight;
    velocity = muzzleVelocity;
    time = 0;

    System.out.println("TIME    HEIGHT    VELOCITY");
    System.out.println("----    ------    --------");

    while (height > 0) {
        if ((time % 1.0) < DELTA_T) {
            System.out.printf("%6.2f%10.3f%10.3f\n", time, height, velocity);

        }
        height = (height + (velocity * time));
        velocity = (velocity - (GRAVITY * time));
        time = (time + 0.001);

    }

}

}

Answer 1

您将按速度 * 时间增加高度，这是每次迭代的绝对时间量。您需要将其增加时间增量 DELTA_T

例如:

while (height > 0) {
    if ((time % 1.0) < DELTA_T) {
        System.out.printf("%6.2f%10.3f%10.3f\n", time, height, velocity);

    }
    height = (height + (velocity * DELTA_T));
    velocity = (velocity - (GRAVITY * DELTA_T));
    time = (time + DELTA_T);

}

还值得注意的是，重力通常应该是负值，以便您可以将其添加到速度中，就像将速度添加到位置中一样。