Question

如果我输入基数和指数，我设法得到结果，但输出应该是

例如：输出应该如下所示

>> base：5 exponent：2

5 ^ 2 = 25
  5 ^ 1 = 5

我需要帮助才能在某个地方放置一些东西来实现这一目标......

import java.util.Scanner;

public class recursion {

    public static void main(String args[]) {
        Scanner scanner = new Scanner(System.in);
        int base = 0;
        int expo = 0;

        System.out.print("Enter number for base ");
        for (int i = 0; i < 1; i++)
            base = scanner.nextInt();

        System.out.print("Enter number for exponent ");
        for (int j = 0; j < 1; j++)
            expo = scanner.nextInt();

        System.out.println(base + "^" +expo +" = " +  pow(base,expo));

    }


    public static int pow(int x, int p) {

        System.out.println(x + "^" +p +" = " );
        if (p == 0)
            return 1;
        if (p % 2 == 0) {
            int a = pow(x, (p / 2));
            return  a * a; // This line
        } else {
            int a = pow(x, ((p - 1) / 2));
            return x * a * a; // This line
        }

    }

}

Answer 1

首先，以下代码段需要审核：

{
    for (int i = 0; i < 1; i++)
    /*
     * This for loop is unnecessary.
     * It asserts that the following clause is run only once,
     * which is true for any statements anyway.
     */
        // ...
}

    return a * a;
} /* if (p % 2 == 0) */ else {
    /*
     * Statements are unnecessarily nested within else clause.
     * The corresponding then clause does not complete normally.
     * Moving the following code snippet out of an else block
     * would have the same effect, but simplifies the control
     * statements.
     */
    int a = pow(x, ((p - 1) / 2));
    return x * a * a;
}

在pow()方法中，您使用System.out.println()方法。你正在调用它进行调试，但是当进程正常返回时它是不必要的。当您正在寻找将指数的操作打印为“来自用户指定的指数 - > 1”（“按降序”）时，使用循环打印您的System.out.println(base + "^" + expo + " = " + TestClass.pow(base, expo));：

    do // New!
        System.out.println(base + "^" + expo + " = " + TestClass.pow(base, expo));
    while (expo-- > 1); // New!

} /* main( args ) */

您可以删除pow()中的调试行。

示例：（>>表示STDIN）

输入基数>> 5的数字   输入指数>>的数字2
  5 ^ 2 = 25
  5 ^ 1 = 5

输入基数>> 4的数字   输入指数>>的数字5
  4 ^ 5 = 1024
  4 ^ 4 = 256
  4 ^ 3 = 64
  4 ^ 2 = 16
  4 ^ 1 = 4

View a live code demo.

Answer 2

void power(int base, int exp){

//Use for loop to iterate through each exp down to 0
for(int i=exp; i>=0; i--){
     int result= exponent(base,i);
     System.out.println(base + "^" + i + "=" + result)//Will display result as 5^2=25
}

//递归计算b ^ e。

的结果

int exponent(int b, int e){
 if(e==0){//Base case occurs when e=0.
    return (1);
  }
return (b * exponent(b,e-1));
}

如何在java中以降序打印结果？

2 个答案: