merge two arrays together in C

  /* arr1 and arr2 are two arrays of the same size */ 
  int size = sizeof(arr1)/sizeof(arr1[0]); 
  
  int arr3[size*2]; 
  
  int k = 0; 
	
  for (int i=0; i<size; i++) 
  { 
    arr3[k] = arr1[i]; 
    k++; 
    arr3[k] = arr2[i]; 
    k++; 
  } 

This code merges two arrays, arr1 and arr2, into one new array arr3. First, the size of arr1 is determined and stored in the variable size. Then, a new array arr3 is created with a size of double the size of arr1. The variable k is used as an index and is set to 0. A loop is then initiated that iterates over each element in arr1. At each iteration, the element of arr1 is stored into the current index of arr3, k is incremented by 1, and finally the corresponding element from arr2 is stored into arr3 at the updated index value of k. This loop continues until all elements from both arr1 and arr2 are stored and the merged array arr3 is created.