Day#30 'C' Coding Challenge

What is the output of the below program?

#include <stdio.h> void main() { int arr1[] = {1,2,3,4,5,6,7}; printf("%d\n%d\n%d\n%d\n",sizeof(arr1[0]),sizeof(arr1[1+1]),sizeof(*arr1),sizeof(arr1)); }

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The above code tests below scenarios:

1. Accessing an array using index

2. What happens when array index is incremented

3. Determining the size of the array pointer

4. Determine the array size

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The array arr1[] is an integer array and is accessed using different options.

• arr1[index] accesses the element of an array. So, arr1[0] is the first element of the array as array index starts with zero
• In arr1[index+number], the array index is increased by number count and corresponding element in the array shall be accessed
• *arr1 is a pointer and points to an address of the array element. 
• arr1 accesses the array itself 

The actual output of the code is asking for sizeof each points above and the output shall be:

• sizeof(arr1[0]) shall output size of integer and is 4 bytes
• sizeof(arr1[1+1]) shall output size of integer and is 4 bytes
• sizeof(*arr1) shall output size of integer pointer and is 4 bytes
• sizeof(arr1) shall output size of integer array and is (number of elements * 4 bytes) = 7*4 = 28 Bytes