java - 使用for循环在静态add方法中获取总和并将其返回给main方法

Question

我在静态方法中无法正确使用 for 循环，因此我可以获得两个端点之间偶数的总和并将总和返回到 main 方法。这样做会怎样？

import java.util.Scanner;

public class Calculate {



public static void main(String[] args) {

    Scanner keyboard = new Scanner(System.in);

    int num1, num2;

    System.out.print("Enter two integers: ");
    num1 = keyboard.nextInt();
    num2 = keyboard.nextInt();

    String input;
    System.out.println("Enter a string: ");
    input = keyboard.next();



    if(input.equals("add"))
    {
        while(num1%2==0 && num1<num2)
        {
            int sum;
            sum = add(num1, num2);
            System.out.print("The sum of two integers is: " + sum);
            System.exit(0);
        }
    }
    else if(input.equals("multiply"))
    {
        int product;
        product = multiply(num1, num2);
        System.out.print("The product of two integers is: " + product);
    }
    else
    {
        System.out.println("Error, invalid input!");
    }




}   
public static int add(int number1, int number2)
{
    for(add = 0, add > 0, ++add)
    {   
    int result;
    result = number1 + number2;
    return result;
    }
}
public static int multiply(int number1, int number2)
{
    int result;
    result = number1 * number2;
    return result;
}

}

Answer 1

为什么要用循环等等。 为什么不使用公式？

SUM OF EVEN NUMBERS:

Formula: N(N+1) How to Find N = (First Even + Last Even)/2 - 1

Example: 2+4+6+ ....... 100 N = (2+100)/2 - 1 = 50

Sum of first 50 positive even integers = (50)(51) = 2550

http://www.beatthegmat.com/formula-for-consecutive-even-odd-integers-t17241.html