GATE CSE 2019 | Question: 18

Question

Consider the following C program :

#include<stdio.h>
int jumble(int x, int y){
    x = 2*x+y;
    return x;
}
int main(){
    int x=2, y=5;
    y=jumble(y,x);
    x=jumble(y,x);
    printf("%d \n",x);
    return 0;
}

The value printed by the program is ______________.

Comments

26

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This question Littile try to Trick you

Answer 1

$x = 2, y = 5$

$y =$ jumble$(5,2)$ //call by value and $y$ will hold return value. After this call $x = 2, \: y = 12$

$x =$ jumble$(12, 2)$ //call by value and $x$ will hold return value. After this call $x = 26, \: y = 12$

$x=26$

Comments

if return statement not given then value of x y not changed it works just simple call by value

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@Ram Swaroop If we remove return statement from jumble(), still output is coming to be 26.

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@GravitonQR This is true only in call by reference. In C, function arguments are passed using call by value, so the return statement is needed to update the variables in main(). Without the return statement, the changes made to x inside jumble() will not affect the variables in main().

Answer 2

jumble function is just taking 2 arguments say arg1 and arg2. and returning (2*arg1) + arg2

in main function we have below:

y=jumble(5,2);---main called jumble function with arguments 5,2 initially  and result was stored in variable y

here y becomes 12  i.e: (2*10)+2

x remains same which is 2

x=jumble(12, 2);----main again called jumble function with arguments 12,2  and stored in variable x

so x becomes 26   i.e: (2*12)+2

finally x will be printed
output: 26

 

Answer 3

1st jumble will return 12 that will be stored in y.

this y will be passed as parameter in 2nd jumble that will return 26 in x.

Answer 4

y=jumble(5,2) will return 12 and

x=jumble(12,2) will return 26

so pf(x)-->26

Answer---26

Answer 5

Following is the solution to this question: