Campus Drive Questions and Answers

Campus Drive Questions and Answers 

Q) What are main characteristics of C language?

Ans)

C is a procedural language. The main features of C language include low-level access to memory, simple set of keywords, and clean style. These features make it suitable for system programming like operating system or compiler development.

Q) What is difference between i++ and ++i?

Ans

1) The expression ‘i++’ returns the old value and then increments i. The expression ++i increments the value and returns new value.

2) Precedence of postfix ++ is higher than that of prefix ++.

3) Associativity of postfix ++ is left to right and associativity of prefix ++ is right to left.

4) In C++, ++i can be used as l-value, but i++ cannot be. In C, they both cannot be used as l-value.

Q) What are entry control and exit control loops?

Ans.

 C support only 2 loops:

1.     Entry Control: This loop is categorized in 2 part

a. while loop

b. for loop

2.     Exit control: In this category, there is one type of loop known as

a. do while loop

Q) Why pre-processor directive does not have a semi-colon at last?

Ans

Semi-colon is needed by the compiler and as the name suggests Preprocessors are programs that process our source code before compilation.Therefore the semi-colon is not required.

Q) What is the difference between including the header file with-in angular braces < > and double quotes ” “?

Ans

 If a header file is included within < > then the compiler searches for the particular header file only within the built-in include path. If a header file is included within ” “, then the compiler searches for the particular header file first in the current working directory, if not found then in the built-in include path.

Q) How will you print “Hello World” without semicolon?

Ans

Void main()

{

            if (printf("Hello World"))

}

Program 1:

#include <stdio.h> 

void fun() 

{ 

            // static variables get the default value as 0. 

            static int x; 

            printf("%d ", x); 

            x = x + 1; 

} 

int main() 

{ 

            fun(); 

            fun(); 

            return 0; 

} 

Output: 0 1

Program 2:

#include <stdio.h>

main()

{

            int i;

            int *pi = &i;

            scanf("%d", pi);

            printf("%d\n", i+5);

}

Output: On execution, the value printed is 5 more than the integer value entered.

Program 3:

void main()

{

            int i=-3,j=2,k=0,m;

            m=++i && ++j || ++k;

            printf("%d %d %d %d",i,j,k,m);

}

Ans

-2  3 0 1

Program 4:

int f(int j)

{

static int i = 50;

int k;

if (i == j)

{

            printf("something");

            k = f(i);

            return 0;

}

else return 0;

}

Ans

The function will exhaust the runtime stack or run into an infinite loop when j = 50

Program 5:

Assume the following C variable declaration

int *a[10],b[10[10];

Of the following expressions

i a[2]

ii a[2][3]

iii b[1]

iv b[2][3]

which will  give compile-time errors

Ans:

b[1]

Program 6:

Consider the following declaration of a ‘two-dimensional array in C:

Char a[100][100];

Assuming that the main memory is byte-addressable and that the array is stored starting from memory address 0, the address of a[40][50]

Ans

Address a[i][j] = base address + element size (maximum number of columns * i +  j )

          a[40][50] = 0 + 1 (100 *40 + 50 )

          a[40][50] = 4050

Program 7:

Consider the following declaration of a ‘two-dimensional array in C:

Char a[10][20][30]; i.e a[M][N][O]

Assuming that the main memory is byte-addressable and that the array is stored starting from memory address 0, the address of a[4][5][6] i.e a[i][j][k]

Ans

Address a[i][j][k] = base address + element size (i*N*O + j*O  + k )

          a[4][5][6] = 0 + 1 (4 * 20 * 30 + 5 * 30 + 6 )

          a[4][5][6] =   2400 + 150 + 6

          a[4][5][6] =   2556

Program 8:

What will be the output of the following C program segment?

char inchar = 'A';

switch (inchar)

{

case 'A' :

            printf ("choice A \n") ;

case 'B' :

            printf ("choice B ") ;

case 'C' :

case 'D' :

case 'E' :

default:

            printf ("No Choice") ;

}

Ans:

choice A

choice B No Choice

Program 9:

What will be the output of the following C program segment?

char p[20];

char *s = "string";

int length = strlen(s);

int i;

for (i = 0; i < length; i++)

            p[i] = s[length — i];

printf("%s",p);

Ans

no output is printed

Explanation:

 Let us consider below line inside the for loop
p[i] = s[length — i];
For i = 0, p[i] will be s[6 — 0] and s[6] is ‘\0’
So p[0] becomes ‘\0’. It doesn’t matter what comes in p[1], p[2]….. as P[0] will not change for i >0. Nothing is printed if we print a string with first character ‘\0’

Program 10:

Consider the following C program

main()

{

   int x, y, m, n;

   scanf ("%d %d", &x, &y);

   /* x > 0 and y > 0 */

   m = x; n = y;

   while (m != n)

   { 

      if(m>n)

         m = m - n;

      else

         n = n - m;

   }

   printf("%d", n);

}

Ans:

GCD (greatest common divisor ) of x and y

Program 11:
#include<stdio.h>
void main()
{
float x=16.3;
if(x==16.3)
printf("HAI");
else
printf("Hello");
}

output :

Program 12:
#include<stdio.h>
#define size 2+4
void main()
{
printf("%d",size*size);
}

output:

Program 13:
#include<stdio.h>
void main()
{
int i=1;
printf("\n %d\n %d\n %d\n %d",i++,i++,i++,i++);
}


output:

Program 14:
#include<stdio.h>
void main()
{
int i=5;
printf("\n %d\n %d\n %d\n %d\n %d",i++,i--,++i,--i ,i);
}

output:

Program 15:
#include<stdio.h>
void main()
{
int a[]={1,2,3,4,5,6};
printf("%d",1[a]);
}

output:

Program 16:
#include<stdio.h>
int sum (int);
int sum (int n)
{
 if(n<1)
  return n;
 else
  return (n + sum(n-1));
}
void main()
{
 sum(5);
 printf("sum is %d ",sum(5));
}

Answer : 15

Program 17:
#include<stdio.h>
void sum (int ,int ,int );
void sum (int x,int y,int z)
{
 y=y+1;
 z=z+x;
}
void main()
{
 int a=2,b=3;
 sum((a+b),a,a);
 printf("sum is %d ",a);
}
 
Answer: 2

 

Program 17: