printf("%d", arr[n-1]);
printArray(n-1, arr);

#include <stdio.h>

void printArray(int n, int arr[]);

int main(void){

    int array[7]= {1,2,3,4,5,6,7}, n=7;
    printArray(n, x);

    return 0;
}

void printArray(int n, int arr[]){

   if( n==1){
      printf("%d", arr[0])
   }
   else {
      printf("%d", arr[n-1]);
      printArray(n-1, arr);
   }
}

printArray( 5, array ):
  printf( "%d", arr[4] );
  printArray( 4, arr ):
    printf( "%d", arr[3] );
    printArray( 3, arr ):
      printf( "%d", arr[2] );
      printArray( 2, arr ):
        ...

printArray( n-1, arr );
printf( "%d", arr[n-1] );

printArray( 5, arr ):
  printArray( 4, arr ):
    printArray( 3, arr ):
      printArray( 2, arr ):
        printArray( 1, arr ):
          printf( "%d", array[0] );
        printf( "%d", array[1] );
      printf( "%d", array[2] );
      ...