Java 程序计算数组中元素的出现次数

编写一个 Java 程序，使用 for 循环计算数组中元素的出现次数。此程序接受数组的大小、数组元素以及要搜索的项目。

for 循环会遍历数组中的每个元素，if 语句会将该元素与数字进行比较。如果两者都匹配，则出现次数变量会加一。最后，我们将出现次数变量作为输出打印出来。

package NumPrograms;

import java.util.Scanner;

public class ArrayCountOccrence1 {
	private static Scanner sc;
	
	public static void main(String[] args) {
		int Size, i, num, occr = 0;
		
		sc = new Scanner(System.in);
		
		System.out.print("Please Enter the Array size = ");
		Size = sc.nextInt();
		
		int[] arr = new int[Size];
		
		System.out.format("Enter the Array %d elements : ", Size);
		for(i = 0; i < Size; i++) 
		{
			arr[i] = sc.nextInt();
		}
		
		System.out.print("Please Enter the Array Item to Know = ");
		num = sc.nextInt();
		
		for(i = 0; i < arr.length; i++) 
		{
			if(arr[i] == num)
			{
				occr++;
			}
		}
		
		System.out.println(num + " Occurred " + occr + " Times.");
	}
}

此 Java 程序使用 while 循环计算数组中元素的出现次数。

package NumPrograms;

import java.util.Scanner;

public class ArrayCountOccrence2 {
	private static Scanner sc;
	
	public static void main(String[] args) {
		int Size, i, num, occr = 0;
		
		sc = new Scanner(System.in);
		
		System.out.print("Please Enter the size = ");
		Size = sc.nextInt();
		
		int[] arr = new int[Size];
		
		System.out.format("Enter the %d elements : ", Size);
		i = 0;
		while( i < Size) 
		{
			arr[i] = sc.nextInt();
			i++;
		}
		
		System.out.print("Please Enter the Array Item to Know = ");
		num = sc.nextInt();
		
		i = 0;
		while( i < arr.length) 
		{
			if(arr[i] == num)
			{
				occr++;
			}
			i++;
		}
		
		System.out.println(num + " Occurred " + occr + " Times.");
	}
}

Please Enter the size = 7
Enter the 7 elements : 22 9 22 7 54 22 1
Please Enter the Array Item to Know = 22
22 Occurred 3 Times.

此 示例 使用 do while 循环来计算给定数组中元素的出现次数。

package NumPrograms;

import java.util.Scanner;

public class ArrayCountOccrence3 {
	private static Scanner sc;
	
	public static void main(String[] args) {
		int Size, i, num, occr = 0;
		
		sc = new Scanner(System.in);
		
		System.out.print("Please Enter the Item to Know = ");
		num = sc.nextInt();
		
		System.out.print("Please Enter the size = ");
		Size = sc.nextInt();
		
		int[] arr = new int[Size];
		
		System.out.format("Enter the %d elements : ", Size);
		i = 0;
		do
		{
			arr[i] = sc.nextInt();
			if(arr[i] == num)
			{
				occr++;
			}

		} while(++i < Size);
		
		System.out.println(num + " Occurred " + occr + " Times.");
	}
}

Please Enter the Item to Know = 5
Please Enter the size = 9
Enter the 9 elements : 5 2 5 9 11 5 22 7 5
5 Occurred 4 Times.