﻿ C Program: 5 in an array must be next to another 5

# C Exercises: Check a given array of integers and return true if every 5 that appears in the given array is next to another 5

## C-programming basic algorithm: Exercise-65 with Solution

Write a C program to check a given array of integers and return true if every 5 that appears in the given array is next to another 5.

C Code:

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

// Function prototype for 'test'
int test(int numbers[], int arr_len);

int main(void){
int arr_size;

// Declaration and initialization of an integer array 'array1'
int array1[] = {3, 5, 5, 3, 7};
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[] = {3, 5, 5, 4, 1, 5, 7};
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[] = {3, 5, 5, 5, 5, 5};
arr_size = sizeof(array3)/sizeof(array3[0]);

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

// Declaration and initialization of an integer array 'array4'
int array4[] = {3, 5, 5, 5, 5, 5};
arr_size = sizeof(array4)/sizeof(array4[0]);

// Printing the result of the 'test' function for 'array4'
printf("\n%d",test(array4, arr_size));
}

// Definition of the 'test' function
int test(int numbers[], int arr_len)
{
int flag = 0;

// Looping through the elements of the array
for (int i = 0; i < arr_len; i++)
{
if (numbers[i] == 5)
{
// Checking if adjacent elements are also 5
if ((i > 0 && numbers[i - 1] == 5) || (i < arr_len - 1 && numbers[i + 1] == 5))
flag = 1;
else if (i == arr_len - 1)
flag = 0;
else
return 0;
}
}

// Returning 'flag' indicating if there are adjacent 5s
return flag;
}
``````

Sample Output:

```1
0
1
1
```

Pictorial Presentation:

Flowchart:

C Programming Code Editor:

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