C Exercises: Check whether a given array of integers contains 5 next to a 5 somewhere

Last update on July 28 2025 12:49:58 (UTC/GMT +8 hours)

54. Check for Adjacent 5's in Array

Write a C program to check whether a given array of integers contains 5 next to a 5 somewhere.

C Code:

#include <stdio.h>
#include <stdlib.h>

// Function prototype for 'test'
int test(int nums[], int arr_size);

int main(void){
    // Declaration and initialization of variables
    int arr_size;

    // Declaration and initialization of an integer array 'array1'
    int array1[] = {1, 5, 6, 9, 10, 17};

    // Calculating the size of the array 'array1'
    arr_size = sizeof(array1)/sizeof(array1[0]);

    // Printing the result of the 'test' function for 'array1'
    printf("%d",test(array1, arr_size));

    // Declaration and initialization of an integer array 'array2'
    int array2[] = {1, 5, 5, 9, 10, 17};

    // Calculating the size of the array 'array2'
    arr_size = sizeof(array2)/sizeof(array2[0]);

    // Printing the result of the 'test' function for 'array2'
    printf("\n%d",test(array2, arr_size));

    // Declaration and initialization of an integer array 'array3'
    int array3[] = {1, 5, 5, 9, 10, 17, 5, 5};

    // Calculating the size of the array 'array3'
    arr_size = sizeof(array3)/sizeof(array3[0]);

    // Printing the result of the 'test' function for 'array3'
    printf("\n%d",test(array3, arr_size));
}    

// Definition of the 'test' function
int test(int nums[], int arr_size)
{
    // Looping through the elements of the array
    for (int i = 0; i < arr_size - 1; i++)
    {
        // Checking if the current element and the next element are both 5
        if (nums[i] == 5 && nums[i] == nums[i + 1])
        {
            return 1; // If condition met, return 1 (true)
        }
    }

    return 0; // If condition not met for any pair, return 0 (false)
}

Sample Output:

0
1
1

Pictorial Presentation:

Flowchart:

For more Practice: Solve these Related Problems:

• Write a C program to verify if an array contains adjacent pairs of even numbers.
• Write a C program to check if an array has two consecutive numbers that are both prime.
• Write a C program to detect if an array contains two consecutive identical numbers, regardless of their value.
• Write a C program to check if an array contains a 7 immediately followed by another 7.

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