﻿ C : Count the number of pairs of 5s in an array of integers # C Exercises: Count the number of two 5's are next to each other in an array of integers

## C-programming basic algorithm: Exercise-15 with Solution

Write a C program to count the number of two 5's are next to each other in an array of integers. Also count the situation where the second 5 is actually a 6.

C Code:

``````#include <stdio.h>
#include <stdlib.h>
int main(void){
int arr_size;
int array1[] = {5, 5, 2 };
arr_size = sizeof(array1)/sizeof(array1);
printf("%d",test(array1, arr_size));
int array2[] = {5, 5, 2, 5, 5 };
arr_size = sizeof(array2)/sizeof(array2);
printf("\n%d",test(array2, arr_size));
int array3[] = {5, 6, 2, 9 };
arr_size = sizeof(array3)/sizeof(array3);
printf("\n%d",test(array3, arr_size));
}

int test(int nums[], int arr_size)
{
int ctr = 0;
for (int i = 0; i < arr_size - 1; i++)
{
if (nums[i] == 5 && (nums[i + 1] == 5 || nums[i + 1] == 6)) ctr++;
}
return ctr;
}
``````

Sample Output:

```1
2
1
```

Pictorial Presentation: Flowchart: C Programming Code Editor:

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## C Programming: Tips of the Day

Why doesn't a+++++b work?

printf("%d",a+++++b); is interpreted as (a++)++ + b according to the Maximal Munch Rule!.

++ (postfix) doesn't evaluate to an lvalue but it requires its operand to be an lvalue.

! 6.4/4 says the next preprocessing token is the longest sequence of characters that could constitute a preprocessing token"

Ref : https://bit.ly/3fdldUT