What is the output of the following code fragment?
Int f1int n, int m)
{
Ifn

Question

What is the output of the following code fragment?
Int f1int n, int m)
{
Ifn < m)
Return 0;
Else ifn==m)
Return m+ f1n-1,m);
Else
Return n+ f1n-2,m-1);
}
Int main)
{
Cout << f15,4);
Return 0;
}
A) 0
B) 2
C) 4
D) 8
E) infinite recursion

Quizplus · Accepted Answer

The code is implementing a recursive function to calculate the sum of two integers n and m, where n is always greater than or equal to m. 
In the main function, we are calling the function f1 with parameters 15 and 4. 
The first if statement checks if n is less than m, which is not the case. 
Then the else if statement checks if n is equal to m, which also fails. 
So, the else statement is executed, which returns the sum of n and the result of f1 with parameters n-2 and m-1. 
This continues until the base case when n=m, which is reached when n=4. 
At this point, the function returns the value of m+ f1(3,4), which is 4 + (3+ f1(1,3)). 
The next step is to calculate f1(1,3), which is equal to 3 + f1(0,2). 
The final step is to calculate f1(0,2), which is equal to 2 + f1(-1,1). 
Since n is less than m at this point, the if statement is true and the function returns 0. 
So the final result of f1(15,4) is 4 + 3 + 2 + 0 = 9. Therefore, the output of the program is 9, which corresponds to choice D.

What Is the Output of the Following Code Fragment