Array is not required , this will do it for(i=0;i < no;i++) {
scanf("%d",&input); if(input == key) printf("%d",i); }

Its a very basic question and I dont know why they have given 30 points. only 3 lines of code is enough to solve

Here is Python 3 solution from my HackerrankPractice repository:

v = int(input())
n = int(input())
arr = list(map(int, input().split()))
i = 0
while arr[i] != v:
    i += 1
print(i)

Feel free to ask if you have any questions :)

My solution in Python3:

def introTutorial(V, arr):
  return arr.index(V)

Javascript solution:

return arr.indexOf(V);