Check fibonacci series program in c

Check fibonacci series >>

Input type: Integer(number)

Input: 10

Output: 0 1 1 2 3 5 8 13 21 34

Constraints:

number>5 and number<=20

If Input number given by user is space, character or empty display "INVALID INPUT".

CODE in C:

#include<stdio.h>

int main()

{

 int n1=0,n2=1,n3,i,number;

 printf("Enter the number of elements:");

 scanf("%d",&number);

 if(number<=5 || number>20){

    printf("INVALID INPUT");

 }

 else{

 printf("\n%d %d",n1,n2);

 for(i=2;i<number;++i){

  n3=n1+n2;

  printf(" %d",n3);

  n1=n2;

  n2=n3;

 }

 }

  return 0;

 }

OUTPUT :

Enter the number of elements:10

0 1 1 2 3 5 8 13 21 34