Pass-by-value
Question 1 |
What is the return value of f(p,p), if the value of p is initialized to 5 before the call? Note that the first parameter is passed by reference, whereas the second parameter is passed by value.
int f(int &x, int c) { c = c - 1; if (c==0) return 1; x = x + 1; return f(x,c) * x;} |
3024 | |
6561 | |
55440 | |
161051 |
Question 1 Explanation:
Since it is f(p,p)
f(5,5)→f(x,4)*x
f(x,3)*x*x
f(x,2)*x*x*x
⇒x*x*x*x=x4
Now x=x+1, there are 4 different calls namely f(6,4),f(7,3),f(8,2),f(9,1)
Because of pass by reference, x in all earlier functions is replaced with 9.
⇒ 9*9*9*9=94=6561
f(5,5)→f(x,4)*x
f(x,3)*x*x
f(x,2)*x*x*x
⇒x*x*x*x=x4
Now x=x+1, there are 4 different calls namely f(6,4),f(7,3),f(8,2),f(9,1)
Because of pass by reference, x in all earlier functions is replaced with 9.
⇒ 9*9*9*9=94=6561
There is 1 question to complete.