Section 18.4 Practice: Functions And The Stack

Check Your Understanding Check Your Understanding

1.

Suppose you have defined a function “add” as follows:

int add (int a, int b) {
  int sum;
  a = 2;
  sum = a+b;
  return(sum);
}

In your main program, you have declared integer variables a and b and given them the values a = 9 and b = 3. You then call the function add(a,b). What is the value it returns?

I’ll give you a window to try things out in, but you definitely should think this through first by hand before you use the computer to verify your answer. I really want you to think about this first. That’s why you’ll need to write the entire program if you want to use the window below.

2.

Suppose you have defined a function “add” as follows (this is almost the same function as in the previous question):

int add (int a, int b) {
  int sum;
  a = 10;
  sum = a+b;
  return(sum);
}

In your main program, you have declared integer variables a and b and given them the values a = 2 and b = 4. You then call the function add(a,b). What is the value of the variable a in your main program after execution of the function add()?

Another window to try things out... As before, I really want you to think about this first. That’s why you’ll need to write the entire program if you want to use the window below.

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