Question

4. (10 pts) Show the output of the following program: (list the program outputs in the order as they would appear on screen) #include <iostream> using namespace std; int Mystery(int); int main() int x=2, y: y=Mystery(x - 1)+1; cout << "x="«x«", y="«y < endl; y=Mystery( 2 *x); cout << "x="«x«", y="«y < endl; return 0; int Mystery (int num) int y=5; // This is a regular local variable, not a static local variable int result; y=y+num; cout << "y=" <y<", num=" <<num << endl; result =y+num; return (result);

Answer 1

Solution:

Trace the code by each line to check the output printed by the program

In the first statement of Main() function we are declaring a variable x and y variables and initate variable x with value 2.

In next line call the function Mystery() by passing the value x-1 i.e Mystery(1) and then add the value 1 to returned the result and store in variable y.

In Mystery() function

we are declaring a variable y and initializing value as 5 and in next line declaring a variable result of type int.

in next line y=y+num i.e y=5+1=6

In next line we are printing the values y and num the output is

y=6, num=1

in next line modify result variable result=y+num i.e result=7 and then return the result.

The execution will go to main function and will print the x and y values so the output is

x=2, y=8

In next line call the Mystery() function by passing 2*x value is 2*2=4 i.e Mystery(4)

Now the execution will go to Function Mystery()

In Mystery() function

y value will be y+num i.e =5+4=9

so the output printed in the function is

y=9, num=4

In next line we are modifying the result result=num+y=13 will be returned

so the output printed in main function is

x=2, y=13

So the final output is

y=6, num=1

x=2, y=8

y=9, num=4

x=2, y=13

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