#include long int

multiplyNumbers(int n);

int main()
{

int n; _ printf("Enter a positive integer: ");
scanf("%d", &n); = printf("Factorial of %d =

%ld", n, multiplyNumbers(n)); — return 0;

}
long int multiplyNumbers(int n)
{
if (n >= 1) return
n*multiplyNumbers(n-1); 656 return
1;
}
Output

Enter a positive integer: 6

Factorial of 6 = 720

19.a)
Let us see the correct ways for swapping strings:
Method 1(Swap Pointers)

If you are using character pointer for strings (not arrays) then change str1 and str2 to point each other’s
data. 1.6., swap pointers. Ina function, if we want to change a pointer (and obviously we want changes to
be reflected outside the function) then we need to pass a pointer to the pointer.

#include
/* Swaps strings by swapping pointers */ void
swap1(char **str1_ptr, char **str2_ptr)
{
char *temp = *str1_ptr;
*str1_ptr = *str2_ptr;
*str2_ptr = temp;
} int main()

{