Java Array Exercises: Find a missing number in an array
Java Array: Exercise-24 with Solution
Write a Java program to find a missing number in an array.
Pictorial Presentation:

Sample Solution:
Java Code:
import java.util.*;
public class Exercise24 {
public static void main(String[] args) {
int total_num;
int[] numbers = new int[]{1,2,3,4,6,7};
total_num = 7;
int expected_num_sum = total_num * ((total_num + 1) / 2);
int num_sum = 0;
for (int i: numbers) {
num_sum += i;
}
System.out.print( expected_num_sum - num_sum);
System.out.print("\n");
}
}
Sample Data: 1,2,3,4,6,7
Sample Output:
5
Flowchart:

Visualize Java code execution (Python Tutor):
Java Code Editor:
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Java: Tips of the Day
countOccurrences
Counts the occurrences of a value in an array.
Use Arrays.stream().filter().count() to count total number of values that equals the specified value.
public static long countOccurrences(int[] numbers, int value) { return Arrays.stream(numbers) .filter(number -> number == value) .count(); }
Ref: https://bit.ly/3kCAgLb
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