Aptitute question papers in c

C Programs
TYPEDEF

1. What can be said of the following program ?
main()
{
enum Months {JAN =1,FEB,MAR,APR};
Months X = JAN;
if(X==1)
{
printf("Jan is the first month");
}
}
a) Does not print anything
b) Prints : Jan is the first month
c) Generates compilation error
d) Results in runtime error
Answer : b

2.main()
{
extern int i;
i=20;
printf("%d",i);
}

Answer:
Linker Error : Undefined symbol '_i'
Explanation:
extern storage class in the following declaration,
extern int i;
specifies to the compiler that the memory for iis allocated in some other program and that address
will be given to the current program at the time of linking. But linker finds that no other variable of
name iis available in any other program with memory space allocated for it. Hence a linker error has
occurred .

3. enum colors {BLACK,BLUE,GREEN}
main()
{

printf("%d..%d..%d",BLACK,BLUE,GREEN);

return(1);
}
Answer:
0..1..2
Explanation:
enum assigns numbers starting from 0, if not explicitly defined.

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4. Given the following statement enum day = { jan = 1 ,feb=4, april, may} What is the value
of may?
(a) 4
(b) 5
(c) 6
(d) 11
(e) None of the above
Answer c) 6

SWITCH:

5. What is the output of the following program?
main()
{
int l=6;
switch(l)
{ default : l+=2;
case 4: l=4;
case 5: l++;
break;
}
printf("%d",l);
}
a)8 b)6 c)5 d)4 e)none

Answer : c) 5

6. main()
{
int i=3;
switch(i)
{
default:printf("zero");
case 1: printf("one");
break;
case 2:printf("two");
break;
case 3: printf("three");
break;
}
}
Answer :
three
Explanation :
The default case can be placed anywhere inside the loop. It is executed only when all
other cases doesn't match.

7. #include<stdio.h>
main()
{
int i=1,j=2;
switch(i)
{


case 1: printf("GOOD");
break;
case j: printf("BAD");
break;
}
}
Answer:
Compi ler Error: Constant expression required in function main.
Explanation:
The case statement can have only constant expressions (this implies that we cannot
use variable names directly so an error).
Note:
Enumerated types can be used in case statements.

8. main()
{
float i=1.5;
switch(i)
{
case 1: printf("1");
case 2: printf("2");
default : printf("0");
}
}
Answer:
Compi ler Error: switch expression not integral
Explanation:
Switch statements can be applied only to integral types.

10. Output of the following program is
main()
{
int i=0;
for(i=0;i<20;i++)
{
switch(i)
case 0:i+=5;
case 1:i+=2;
case 5:i+=5;
default i+=4;
break;
}
printf("%d,",i);
}
}

a) 0,5,9,13,17
b) 5,9,13,17
c) 12,17,22
d) 16,21
e) Syntax error

Ans. (d)


11. main()
{
int i;
for(i=0;i<3;i++)
switch(i)
{
case 1: printf("%d",i);
case 2 : printf("%d",i);
default: printf("%d"i);
}
}
Answer: 011122

FUNCTIONS:

12. What is the output of the following program?
main()
{
int x=20;
int y=10;
swap(x,y);
printf("%d %d",y,x+2);
}
swap(int x,int y)
{
int temp;
temp =x;
x=y;
y=temp;
}

a) 10,20 b) 20,12 c) 22,10 d)10,22 e)none

Answer : d)10,22

13. Which of the following about the following two declaration is true
i ) int *F()
ii) int (*F)()
Choice :
a) Both are identical
b) The first is a correct declaration and the second is wrong
c) The first declaraion is a function returning a pointer to an integer and the second is a
pointer to function returning int
d) Both are different ways of declarin pointer to a function

Answer : c).

14. main()
{
printf("%p",main);
}


Answer:
Some address will be printed.
Explanation:
Function names are just addresses (just like array names are addresses).
main() is also a function. So the address of function main will be printed. %p in printf specifies that
the argument is an address. They are printed as hexadecimal numbers.

15. main()
{
clrscr();
}
clrscr();

Answer:
No output/error
Explanation:
The first clrscr() occurs inside a function. So it becomes a function call. In the second
clrscr(); is a function declaration (because it is not inside any function).

16. main()
{
int i;
printf("%d",scanf("%d",&i)); // value 10 is given as input here
}
Answer:
1
Explanation:
Scanf returns number of items successfully read and not 1/0. Here 10 is given as input which should
have been scanned successfully. So number of items read is 1.

17. main()
{
show();
}
void show()
{
printf("I'm the greatest");
}
Answer:
Compi er error: Type mismatch in redeclaration of show.
Explanation:
When the compiler sees the function show it doesn't know anything about it. So the
default return type (ie, int) is assumed. But when compiler sees the actual definition
of show mismatch occurs since it is declared as void. Hence the error.
The solutions are as follows:
1. declare void show() in main() .
2. define show() before main().
3. declare extern void show() before the use of show().

18. main()
{
main();
}


Answer:
Runtime error : Stack overflow.
Explanation:
main function calls itself again and again. Each time the function is called its return
address is stored in the call stack. Since there is no condition to terminate the
function call, the call stack overflows at runtime. So it terminates the program and
results in an error.

19. What are the following notations of defining functions known as?
i. int abc(int a,float b)
{
/* some code */
}
ii. int abc(a,b)
int a; float b;
{
/* some code*/
}
Answer:
i. ANSI C notati on
ii. Kernighan & Ritche notation

20. What is printed when this program is executed
main()
{
printf ("%dn",f(7));
}
f(X)
{

if ( x<= 4)
return x;

return f(--x);
}
a) 4
b)5
c) 6
d) 7

Answer : a)

21. what is printed when the following program is compiled and executed?
int func (int x)
{
if (x<=0)
return(1);
return func(x -1) +x;

}
main()


{
printf("%dn",func(5));
}
a) 12
b) 16
c) 15
d) 11

Answer : .b) 16.

22. Find the out put:
main()
{
int a==4
sqrt(a);
printf("%d",a);
}
1).2.0 2). 2 3). 4.0 4). 4
Answer : 2

23. Find the output
main()
{
int a[]={ 2,4,6,8,10 };
int i;
change(a,5);
for( i = 0; i <= 4; i++)
printf("n %d",a[i]);
}
change( int *b, int n)
{
int i;
for( i = 0; i < n; i++)
*(b+i) = *(b+i) + 5;
}
Answer:

24. #include<studio.h>
main()
{
func(1);
}
func(int i){
static char *str[] ={ "One","Two","Three","Four"};
printf("%sn",str[i++]);
return;
}
Answer:- it will give warning because str is pointer to the char but
it is initialized with more values
if it is not considered then the answer is Two */


25. Find the out put:

#include<stdio.h>
/* This problem was asked in PCS Bombay in a walk-in-interview
Write a recursive function that calculates
n * (n-1) * (n-2) * ....... 2 * 1 */

main() {
int factorial(int n);
int i,ans;
printf("n Enter a Number:");
scanf("%d",&i);
ans = factorial(i);
printf("nFactorial by recursion = %dn", ans);
}
int factorial(int n)
{
if (n <= 1) return (1);
else
return ( n * factorial(n-1));
}

Answer :

26.Find the output

#include <stdio.h>
main()
{
int j,ans;
j = 4;
ans = count(4);
printf("%dn",ans);
}

int count(int i)
{
if ( i < 0) return(i);
else
return( count(i-2) + count(i-1));
}
Answer :

/* It is showing -18 as an answer */

27. Find the out put

int x;
main()
{
int x=0;
{


int x=10;
x++;
change_value(x);
x++;
Modify_value();
printf("First output : %dn",x);
}
x++;

change_value(x);
printf("Second Output : %dn",x);
Modify_value();
printf("Third Output : %dn",x);
}

Modify_val ue()
{
return (x+=10);
}
change_value()
{
return(x+=1);
}
Answer :

28. Consider the following program
main()
{
int i=20,*j=&i;
f1(j);
*j+=10;
f2(j);
printf("%d and %d",i,*j);
}
f1(k)
int *k;
{
*k +=15;
}

f2(x)
int *x;
{
int m=*x,*n=&m;
*n += 10;
}

The values printed by the program will be
a) 20 and 55
b) 20 and 45
c) 45 and 45


d) 45 and 55
e) 35 and 35
Answer : c

29. what is printed when the following program is
compiled and executed?

int func (int x)
{
if (x<=0)
return(1);
return func(x -1) +x;
}
main()
{
printf("%dn",func(5));
}

a) 12
b) 16
c) 15
d) 11
Answer : b

STRUCTURE AND UNION:

30. What is the size of the following union. Assume that the size of int =2, size of float =4 and size of
char =1.

Union Tag
{
int a;
float b;
char c;
};

a)2 b)4c)1 d) 7

Answer : b

DATA TYPES
31. What is th output of the fol lowing program?
int x= 0x65;
main()
{
char x;
printf("%dn",x)
}
a) compilation error b) 'A' c) 65 d) unidentified


Answer : c


Aptitute question papers in c

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