C C++ Aptitude questions

Mar 1 • Notes • 36760 Views • 29 Comments on C C++ Aptitude questions

C & C++ is always considered as core of computer languages in modern computer science , From class 11th , 12th till 2nd year of B-Tech students have to read C & C++ as language , This indicates importance of c & C++ as language. Command over these two languages can bring lot of change in orientation of student towards career. These two are also considered as basics and question during placement or any job interview are expected from c & C++. A student trying to make career in computer science can not avoid c & C++ , Here we have formulated few important questions which are asked in any exam from placement to job interview from c & C++. C C++ Aptitude questions as follows.

C C++ Aptitude questions

c c++ aptitude questions answers

Here i have attached some important and most continuously asked C and C++ questions, which will be very useful in any scenario.

(1) What will be output if you will compile and execute the following c code?
struct marks
{
int p:3;
int c:3;
};
void main(){
struct marks s={2,-6};
printf(“%d %d”,s.p,s.c);
}

(a) 2 -6
(b) 2 1
(c) 2 2
(d) Compiler error

Ans:c
Exp: Binary value of 2: 00000010 (Select three two bit)
Binary value of 6: 00000110
Binary value of -6: 11111001+1=11111010
(Select last three bit)

(2) What will be output if you will compile and execute the following c code?
#include
void main(){
int i;
float a=5.2;
char *ptr;
ptr=(char *)&a;
for(i=0;i<=3;i++)
printf(“%d “,*ptr++);
}

(a)0 0 0 0
(b)Garbage Garbage Garbage Garbage
(c)102 56 -80 32
(d)102 102 -90 64

Ans: b
Exp: *ptr++ will increment the address every time so we cant guess the value present in that address

(3) What will be output if you will compile and execute the following c code?
#include
Void main(){
printf(“%s”,”c” “question” “bank”);
}
(a) c question bank
(b) c
(c) bank
(d) cquestionbank

Ans :d
Exp: In c string constant “xy” is same as “x” “y”

(4) What will be output if you will compile and execute the following c code?
#include
int main(){
char *str=”c-pointer”;
printf(“%*.*s”,10,7,str);
return 0;
}

(a) c-pointer
(b) cpointer
(c) cpointer null null
(d) c-point

Answer: (d)
Explanation: Meaning of %*.*s in the printf function:
First * indicates the width i.e. how many spaces will take to print the string and second * indicates how many characters will print of any string.

(5) What will be output if you will compile and execute the following c code?
#include
int main(){
int a=-12;
a=a>>3;
printf(“%d”,a);
return 0;
}
(a) -4 (b) -2 (c) -3 (d) -96

Answer :(b)
Explanation:
Binary value of 12 is: 00000000 00001100
-12 is 2’s com of 12 =>11111111 11110100
While performing 3 left shift value becomes => 111111 111110 => -2

(6) What will be output if you will compile and execute the following c code?
#include
#include
int main(){
printf(“%d %d”,sizeof(“string”),strlen(“string”));
return 0;
}
(a) 7 6
(b) 7 7
(c) 6 7
(d) 6 6

Answer: (a)
Explanation: char has memory of 1 byte so sizeof(“string”)=>7 including null char; strlen(“string”)=>6 which is the length.

(7) What will be output if you will compile and execute the following c code?
#include
int main(){
int a=1,2;
int b=(1,2);
printf(“%d %d”,a,b);
return 0;
}
(a)1,1
(b)1,2
(c)2,1
(d)2,2
Ans:b
Exp:1,2 will think as array and a[0]which is same as a will be assigned as 1
(1,2) comma operator will lead to right most one so it returns 2

(8) What will be output if you will compile and execute the following c code?
#include
int main(){
int i=0;
if(i==0){
i=((5,(i=3)),i=1);
printf(“%d”,i);
}
else
printf(“equal”);
}
(a) 5
(b) 3
(c) 1
(d) equal
Ans :c
Exp: refer previous exp

(9) What will be output if you will compile and execute the following c code?

#include
#define message “union is\
power of c”
int main(){
printf(“%s”,message);
return 0;
}
(a) union is power of c
(b) union ispower of c
(c) union is
Power of c
(d) Compiler error
Ans:b
Exp: If you want to write macro constant in new line the end with the character \.

(10) What will be output if you will compile and execute the following c code?

#include
#define call(x) #x
int main(){
printf(“%s”,call(c/c++));
return 0;
}
(a)c
(b)c++
(c)#c/c++
(d)c/c++
Answer: (d)
Exp:the macro call() will return the string as it is

(11) What will be output if you will compile and execute the following c code?
#include
int main(){
if(printf(“cquestionbank”))
printf(“I know c”);
else
printf(“I know c++”);
return 0;
}
(a) I know c
(b) I know c++
(c) cquestionbankI know c
(d) cquestionbankI know c++
Answer: (c)
Exp: printf() always returns true if it prints somethink

(12) What will be output if you will compile and execute the following c code?
int main(){
int i=10;
static int x=i;
if(x==i)
printf(“Equal”);
else if(x>i)
printf(“Greater than”);
else
printf(“Less than”);
return 0;
}
(a) Equal
(b) Greater than
(c) Less than
(d) Compiler error
Answer: (d)
Exp: we cant allocate value for a static variable dynamically

(13) What will be output if you will compile and execute the following c code?
#include
int main(){printf(“%s”,__DATE__);
return 0;
}
(a) Current system date
(b) Current system date with time
(c) null
(d) Compiler error
Answer: (a)

(14) What will be output if you will compile and execute the following c code?
#include
#define var 3
int main(){
char *cricket[var+~0]={“clarke”,”kallis”};
char *ptr=cricket;
printf(“%c”,*++ptr);
return 0;
}
Choose all that apply:
(A) a
(B) r
(C) l
(D) Compilation error
Answer: (C)
Exp: in the above code cricket[0] will be “clarke” and cricket[1] will be “kallis”
so *ptr=cricket
this will Asian cricket[0] value to *ptr
and *++ptr denotes the second character in the string that is ‘l’

(15) What will be output if you will compile and execute the following c code?
#include
int main(){
int i=5,j;
j=++i+++i+++i;
printf(“%d %d”,i,j);
return 0;
}
(A) 7 21
(B) 8 21
(C) 7 24
(D) 8 24
Answer: (D)
Exp: where j=++i + ++i + ++i;
++ operator have high priority than + so all ++ operator will perform first after that it will like
j=8+8+8;
so j=24

(16)What will be output of the following c program?
#include
int main(){
int class=150;
int public=25;
int private=30;
class = class >> private – public;
printf(“%d”,class);
return 0;
}
(A) 1
(B) 2
(C) 4
(D) Compilation error
Answer: (C)
Exp:Keyword of c++ can be used in c

(17) What will be output if you will compile and execute the following c code?
#include
int main(){
int i=2,j=2;
while(i+1?–i:j++)
printf(“%d”,i);
return 0;
}
(A)1
(B)2
(C)3
(D)4
Answer: (A)
Exp:where i+1 will return 3 but still i is 2
rule: any number other that 0 will be considered as TRUE so the return of 2 will be considered as true and the left expression to ‘:’ will execute to bring it as i=1

(18) What will be output if you will compile and execute the following c code?
#include
int main(){
int i,j;
i=j=2;
while(–i&&j++)
printf(“%d %d”,i,j);
return 0;
}
(A) 2 3
(B) 0 3
(C) 1 3
(D)Infinite loop
Answer: (c)
Exp: in while loop
first time (1 && 2)
so it accepts the first time and print 1 3
second time
in the while loop(0 && 3)
0 will be considered as false
so it will stops

(19)The size of generic pointer in c is 2?
a)true b)false
Answer: a

(20)Int aaaaaaaaa; is a legal variable name
a)true b)false
ans:a

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