Java 程序查找数组中奇数和偶数的总和

编写一个Java程序，使用For循环、While循环和函数通过示例查找数组中奇数和偶数的总和。

Java 程序使用 For 循环查找数组中奇数和偶数的总和

此Java程序允许用户输入大小和数组元素。接下来，它将使用For循环查找此数组中的偶数总和和奇数总和。

import java.util.Scanner;

public class SumOfEvenOdds1 {
	private static Scanner sc;
	public static void main(String[] args) 
	{
		int Size, i, EvenSum = 0, OddSum = 0;;
		sc = new Scanner(System.in);
	 
		System.out.print(" Please Enter Number of elements in an array : ");
		Size = sc.nextInt();	
		
		int [] a = new int[Size];
		
		System.out.print(" Please Enter " + Size + " elements of an Array  : ");
		for (i = 0; i < Size; i++)
		{
			a[i] = sc.nextInt();
		}   

		for(i = 0; i < Size; i++)
		{
			if(a[i] % 2 == 0)
			{
				EvenSum = EvenSum + a[i]; 
			}
			else
			{
				OddSum = OddSum + a[i]; 
			}
		}		
		System.out.println("\n The Sum of Even Numbers in this Array = " + EvenSum);
		System.out.println(" The Sum of Odd Numbers in this Array = " + OddSum);
	}
}

任何可被2整除的数字都是偶数。If语句将检查当前数组元素除以2的余数是否恰好等于0。

• 如果条件为True，则为偶数，Java编译器会将该值添加到EvenSum。
• 如果条件为False，则为奇数。编译器会将该值添加到OddSum。

for(i = 0; i < Size; i++) {
	if(a[i] % 2 == 0) {
		EvenSum = EvenSum + a[i]; 
	}
	else {
		OddSum = OddSum + a[i]; 
	}
}

用户插入的数组值为a[5] = {10, 15, 20, 55, 95}}

第一次迭代： for (i = 0; 0 < 5; 0++)
i的值将为0，For循环条件（i < 5）为True。

if(a[i] % 2 == 0) => if(a[0] % 2 == 0)
if(10 % 2 == 0) – 条件为True。

EvenSum = EvenSum + a[0]
EvenSum = 0 + 10 = 10

第二次迭代： for (i = 1; 1 < 5; 1++)
条件 (i < 5) 为 True。

if(a[1] % 2 == 0)
if(15 % 2 == 0) – 条件为False。

OddSum = OddSum + a[1]
OddSum = 0 + 15 = 15

第三次迭代： for (i = 2; 2 < 5; 2++)
i的值将为0，条件（i < 5）为True。

if(a[2] % 2 == 0)
if(20 % 2 == 0) – 条件为True。

EvenSum = EvenSum + a[2]
EvenSum = 10 + 20 = 30

对剩余的迭代执行相同的操作，直到条件 (i < 5) 不满足为止。

Java 程序使用 While 循环查找数组中奇数和偶数的总和

此程序计算数组中奇数和偶数的总和与上面相同。但这次，我们使用了Java While循环。

import java.util.Scanner;

public class SumOfEvenOdds2 {
	private static Scanner sc;
	public static void main(String[] args) 
	{
		int Size, i = 0, j = 0, EvenSum = 0, OddSum = 0;;
		sc = new Scanner(System.in);
	 
		System.out.print(" Please Enter Number of elements in an array : ");
		Size = sc.nextInt();	
		
		int [] a = new int[Size];
		
		System.out.print(" Please Enter " + Size + " elements of an Array  : ");
		while(i < Size)
		{
			a[i] = sc.nextInt();
			i++;
		}   

		while(j < Size)
		{
			if(a[j] % 2 == 0)
			{
				EvenSum = EvenSum + a[j]; 
			}
			else
			{
				OddSum = OddSum + a[j]; 
			}
			j++;
		}		
		System.out.println("\n The Sum of Even Numbers in this Array = " + EvenSum);
		System.out.println(" The Sum of Odd Numbers in this Array = " + OddSum);
	}
}

 Please Enter Number of elements in an array : 8
 Please Enter 8 elements of an Array  : 15 25 20 40 60 89 97 200

 The Sum of Even Numbers in this Array = 320
 The Sum of Odd Numbers in this Array = 226

Java 程序使用方法查找数组中奇数和偶数的总和

此程序与第一个示例相同。但这次，我们创建了一个单独的方法来计算偶数总和，并创建了另一个方法来计算奇数总和。

import java.util.Scanner;

public class SumOfEvenOdds3 {
	private static Scanner sc;
	public static void main(String[] args) 
	{
		int Size, i, EvenSum = 0, OddSum = 0;
		sc = new Scanner(System.in);	 
		System.out.print(" Please Enter Number of elements in an array : ");
		Size = sc.nextInt();	
		
		int [] a = new int[Size];		
		System.out.print(" Please Enter " + Size + " elements of an Array  : ");
		for (i = 0; i < Size; i++)
		{
			a[i] = sc.nextInt();
		}   
		EvenSum = SumOfEvensinArray(a, Size);
		OddSum = SumOfOddsinArray(a, Size);

		System.out.println("\n The Sum of Even Numbers in this Array = " + EvenSum);
		System.out.println(" The Sum of Odd  Numbers in this Array = " + OddSum);
	}
	public static int SumOfEvensinArray(int[] a, int Size)
	{
		int i, EvenSum = 0;		
		for(i = 0; i < Size; i++)
		{
			if(a[i] % 2 == 0)
			{
				EvenSum = EvenSum + a[i]; 
			}
		}	
		return EvenSum;
	}
	public static int SumOfOddsinArray(int[] a, int Size)
	{
		int i, OddSum = 0;		
		for(i = 0; i < Size; i++)
		{
			if(a[i] % 2 != 0)
			{
				OddSum = OddSum + a[i]; 
			}
		}	
		return OddSum;
	}
}

 Please Enter Number of elements in an array : 10
 Please Enter 10 elements of an Array  : 14 24 59 89 100 209 77 16 125 196

 The Sum of Even Numbers in this Array = 350
 The Sum of Odd  Numbers in this Array = 559