GATE CSE 2014 | Set 2 | Question: 42

Question

Consider the C function given below.

int f(int j)
{ 
    static int i = 50; 
    int k; 
    if (i == j) 
    { 
        printf("something"); 
        k = f(i); 
        return 0; 
    } 
    else return 0; 
} 

Which one of the following is TRUE?

• A. The function returns $0$ for all values of $j$.
• B. The function prints the string something for all values of $j$.
• C. The function returns $0$ when $j = 50$.
• D. The function will exhaust the runtime stack or run into an infinite loop when $j = 50$.

Answer 1

There is no updation for $i$ and $j$ in the function. so if we call function with $j = 50$ the recursive call will be continued infinitely. There is no terminating condition for recursion. hence answer D

Comments

Because when j = 50, the loop condition will be true forever and the program will keep on executing, thus exhausting the stack.

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Exactly my point...

Shouldn't the answer be:

The function will exhaust the runtime stack or terminate abnormally when j=50.

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@akash yes it will terminate abruptly, because of stackoverflow.

Answer 2

1. int f(int j)
 { 
 2.   static int i = 50; 
 3. int k; 
 4.   if (i == j) 
    { 
 5.       printf("something"); 
 6.       k = f(i);              key line function loop from 6 to 1 always when j=50  even not return 0. so 1st and 3rd statement are false.

        return 0; 
    } 
    else return 0; 
} 

since for value other then 50 it will not print anythng  b/c not satisfy if property.

so ans is D. since always same value pass as value.

Answer 3

When j is 50, the function would call itself again and again as neither i nor j is changed inside the recursion.

Answer 4

Option D

Answer 5

Crucial Note:Looking closely at the entire function body, there is absolutely no statement like i++ or i = i-1. The value of remains locked at 50 forever.

Answer 6

So option d is correct.