Question

Analyze the following programs and write down the output of the program. Please print every character (including whitespace character) clearly!

      # include <iostream>

using namespace std;  

int fun( int a )

{

      int b = a * 2;

      return b;

  }

  int main()

  {

      int y = 5;

      cout << fun(y) << endl;

      cout << fun(-- y) << endl;

      cout << fun(y--) << endl;

      cout << y <<endl;

   

      return 0;

  }

Answer 1

Output:

10

8

8

3

Execution Step by Step:

1. y = 5 assigned.
2. fun(5) is called.
3. fun(5) computes b= a*2, passed a=5. So, b=5*2=10.
4. Return value 10 is printed.
5. fun(--y) is called --y is prefix so the y = y-1 = 5-1=4 is done first then fun(4) is called
6. fun(4) computes b= a*2, passed a=4. So,return b=2*4=8
7. Return value 8 is printed.
8. fun(y--) is called y-- is postfix so the y=y stays and after the function execution y decremented by value 1. So fun(4) is called.
9. fun(4) computes b= a*2, passed a=4. So, returns b=2*4=8.
10. Return value 8 is printed.
11. y=y-1 is executed now. So y=y-1=4-1=3.
12. y is 3 here so 3 is the output will be printed.