java - 试图找到负指数的答案，只有正指数和 0 有效

Question

我在寻找答案时无法使用数学课。计算答案时我必须使用 for 循环。

package Powers;

import TerminalIO.KeyboardReader; 

public class powers {
public static void main(String [] args) 
{
    KeyboardReader reader= new KeyboardReader();
    //Variables
    int base; //The base number for the calculations
    int minE; //The minimum exponent that will be used
    int maxE; //The maximum exponent that will be used
    int answer; //Weather the user wishes to repeat or not
    double result = 1; //The result of the base to the power of the exponent

    //Inputs
    do { /* Start of repeat */  base = reader.readInt ("Please enter the base. "); 
    minE = reader.readInt ("Please enter the minimum exponent. ");
    maxE = reader.readInt ("Please enter the maximum exponent. ");
        //Error Checking
        while (minE > maxE) {
            System.out.println("There seems to be an error, your minimum exponent is greater then your maximum exponent. Please re-enter your values");
            minE = reader.readInt("Enter your minimum exponent. ");
            maxE = reader.readInt("Enter your maximum exponent. ");
        }
        //End of Error Checking

    //Calculations          
        //Output    
        System.out.println(" Base          Exponent          Result");
        System.out.println();
        int expo; //The exponent by which the base will be powered to
        for (expo = minE; expo <= maxE; expo++) {

            //For exponent being 0
            result = 1; 
            //For exponent being <0
            if (expo <0) {
                for (int i= minE;i != 0;i = i + 1) {
                    result = result/base;
                }
            }

            if (expo == 0) {
                result = 1 ;
            }

            //For exponent being 1
            if (expo == 1) {
                result = base;
            }
            //For exponent being >1
            if (expo > 1) {
                for (int i=1;i<=expo;i++) {
                    result = result*base;
                }
            }



            System.out.println( "    " + base + "                 " + expo + "             " + result); 
        }
        System.out.println();
        answer = reader.readInt ("Do you wish to repeat? Enter 1 if yes.");
    } while (answer == 1); //End of repeat

}

出现的示例答案是

Please enter the base. 2
Please enter the minimum exponent. -2
Please enter the maximum exponent. 2
Base          Exponent          Result

2                 -2             0.25
2                 -1             0.25
2                 0             1.0
2                 1             2.0
2                 2             4.0

如您所见，只有 0 和积极的工作，而不是消极的。

Answer 1

你对 i 的初始化错误。将 i= minE 改为 i= expo。

for (int i = expo; i != 0; i = i + 1) {
    result = result/base;
}