一个数字出现多少次

Question

I need to write a program that reads an array of ints and an integer number n . The program must check how many times n occurs in the array.

Input:

The first line contains the size of the input array.

The second line contains elements of the array separated by spaces.

The third line contains n.

Output:

The result is only a single non-negative integer number.

My code:

import java.util.Scanner;
class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int len = scanner.nextInt();
        int[] array = new int[len];
        int n = scanner.nextInt();
        for (int i = 0; i < len; i++){
            array[i] = scanner.nextInt();
        }
        int counter = 0;
        for (int i = 0; i < len; i++) {
            if (array[i] == n) {
                counter++;
            }
        }
        System.out.println(counter);
    }
}

Test input:

6

1 2 3 4 2 1

2

My result: 1

My question is why int n = scanner.nextInt(); read "1". It should "2".

Answer 1

Reading the n variable was in the wrong place. The solution:

import java.util.Scanner;
class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int len = scanner.nextInt();
        int[] array = new int[len];
        
        for (int i = 0; i < len; i++){
            array[i] = scanner.nextInt();
        }
        int counter = 0;
        int n = scanner.nextInt();
        for (int i = 0; i < len; i++) {
            if (array[i] == n) {
                counter++;
            }
        }
        System.out.println(counter);
    }
}

Answer 2

You should read n after you read the array like so:

Scanner scanner = new Scanner(System.in);
int len = scanner.nextInt();
int[] array = new int[len];

for (int i = 0; i < len; i++){
    array[i] = scanner.nextInt();
}

int n = scanner.nextInt();

int counter = 0;

for (int i = 0; i < len; i++) {
    if (array[i] == n) {
        counter++;
    }
}
System.out.println(counter);