编写一个程序，提示输入三角形的边长并报告三个角

Question

编写一个程序，提示输入三角形的边长并报告三个角。我没有得到等于180的角度，并且在某些情况下，我得到NaN的某些角度值。我的代码如下所示public static int getSideA() {    System.out.println("What is the length of side a?");    Scanner console = new Scanner(System.in);    int a = console.nextInt();    return a;}public static int getSideB() {    System.out.println("What is the length of side b?");    Scanner console = new Scanner(System.in);    int b = console.nextInt();    return b;}public static int getSideC() {    System.out.println("What is the length of side C");    Scanner console = new Scanner(System.in);    int c = console.nextInt();    return c;}public static void giveSides(int a, int b, int c) {    double angleA = Math.toDegrees(Math.acos((a^2 - b^2 - c^2) / (-2.0 * c * b)));    double angleB = Math.toDegrees(Math.acos((b^2 - a^2 - c^2) / (-2.0 * a * c)));    double angleC = Math.toDegrees(Math.acos((c^2 - a^2 - b^2) / (-2.0 * a * b)));    System.out.println("The three angles are: " + angleA + " " + angleB + " " + angleC);}public static void main(String[] args) {    int a = getSideA();    int b = getSideB();    int c = getSideC();    giveSides(a, b, c);}

Answer 1

问题在于这三行：

double angleA = Math.toDegrees(Math.acos((a^2 - b^2 - c^2) / (-2.0 * c * b)));

double angleB = Math.toDegrees(Math.acos((b^2 - a^2 - c^2) / (-2.0 * a * c)));

double angleC = Math.toDegrees(Math.acos((c^2 - a^2 - b^2) / (-2.0 * a * b)));

^2并不意味着“平方”。它的意思是“按位异或 2”。您需要使用a*a或Math.pow(a, 2)表示“平方”。

所以这三行应该是：

double angleA = Math.toDegrees(Math.acos((a*a - b*b - c*c) / (-2.0 * c * b)));

double angleB = Math.toDegrees(Math.acos((b*b - a*a - c*c) / (-2.0 * a * c)));

double angleC = Math.toDegrees(Math.acos((c*c - a*a - b*b) / (-2.0 * a * b)));

此外，这些getSideX方法可以合并为一个，并且可以将扫描仪提取到类级别：

static Scanner console = new Scanner(System.in);

public static int getSide(String name) {

    System.out.println("What is the length of side " + name + "?");

    int a = console.nextInt();

    return a;

}

您的main方法现在如下所示：

public static void main(String[] args) {

    int a = getSide("A");

    int b = getSide("B");

    int c = getSide("C");

    giveSides(a, b, c);

}