C Array

In C, array is a composite data type. Because we can create an array with the help of primitive data type like int, chat, double etc.

Syntax for creation of one Dimensional array in C

int a[5];

Here a is the array name, type is int. total allocation is 5(5*4=20bytes) here index starts from 0(zero)

Initialization of an array :

int a[]={1,2,3,4,5,6}

if you want access element from above mentioned array, then you can access it with help of index. for example the index of value 3 is 2.

if you want to access all the element from an array, then you can use loop

example : for loop

for(i=0;i<6;i++)

{

   printf("%d\n", a[i]);

}

to calculate size of an array, use the formula :

l=sizeof(a)/sizeof(a[0])

Question & Answer

Choose correct or the best alternative in the following:

Q.1 What is the output of the following program?

main ( )

{ int x = 2, y = 5;

if (x < y) return (x = x+y); else printf (“z1”);

printf(“z2”);

}

(A) z2 (B) z1z2

(C) Compilation error (D) None of these

Ans: D

There is no compilation error but there will no output because function is returning a

value and if statement is true in this case.

Q.2 Choose the correct one

(A) Address operator can not be applied to register variables

(B) Address operator can be applied to register variables

(C) Use of register declaration will increase the execution time

(D) None of the above

Ans: D

A register access is much faster than a memory access, keeping the frequently

accessed variables in the register will lead to faster execution of programs.

Q.3 What is the following program doing?

main ()

{ int d = 1;

do

printf(“%d\n”, d++);

while (d < = 9);}

(A) Adding 9 integers (B) Adding integers from 1 to 9

(C) Displaying integers from 1 to 9 (D) None of these

Ans: C

d starting from 1 is incrementing one by one till d=9 so the printf statement is printing

numbers from 1 to 9.

Q.4 What is the output of the following program?

main ( )

{ extern int x;

x = 20;

printf(“\n%d”, x);

}

(A) 0 (B) 20

(C) error (D) garbage value

Ans: C

Output of the given program will be “Linker error-undefined symbol x”. External

variables are declared outside a function.

Q.5 If x is one dimensional array, then pick up the correct answer

(A) *(x + i) is same as &x[i] (B) *&x[i] is same as x + i

(C) *(x + i) is same as x[i] +1 (D) *(x + i) is same as *x[i]

Ans: A

num[i] is same as *(num+i)

Q.6 Consider the following declaration

int a, *b = &a, **c = &b;

The following program fragment

a = 4;

**c = 5;

(A) does not change the value of a (B) assigns address of c to a

(C) assigns the value of b to a (D) assigns 5 to a

Ans: D

The given statements assigns 5 to a

Q.7 Choose the correct answer

(A) enum variable can not be assigned new values

(B) enum variable can be compared

(C) enumeration feature increase the power of C

(D) None of the above

Ans: C

The enumerated data types give an opportunity to invent our own data typeand define

what value the variable of this data type can take.

Q.8 The content of file will be lost if it is opened in

(A) w mode (B) w+ mode

(C) a mode (D) a+ mode

Ans: A

When the mode is writing, the contents are deleted and the file is opened as a new file.

Q.9 Consider the following code segment:

int a[10], *p1, *p2;

p1 = &a[4];

p2 = &a[6];

Which of the following statements is incorrect w.r.t. pointers?

(A) p1 + 2 (B) p2 – 2

(C) p2 + p1 (D) p2 – p1

Ans: C

Addition of two pointers is not allowed.

Q.10 The second expression (j – k) in the following expression will be evaluated

(i + 5) && (j – k)

(A) if expression (i + 5) is true.

(B) if expression (i + 5) is false.

(C) irrespective of whether (i + 5) is true or false.

(D) will not be evaluated in any case.

Ans: A

In a compound logical expression combined with &&, the second expression is

evaluated only if first is evaluated in true.

In the for statement: for (exp1; exp2; exp3) { … }

where exp1, exp2 and exp3 are expressions. What is optional?

(A) None of the expressions is optional.

(B) Only exp1 is optional.

(C) Only exp1 and exp3 are optional.

(D) All the expressions are optional.

Ans: D

All the expressions are optional. For (;;) is a valid statement in C.

Q.12 The output of the following code segment will be

char x = ‘B’;

switch (x) {

case ‘A’: printf(“a”);

case ‘B’: printf(“b”);

case ‘C’: printf(“c”);

}

(A) B (B) b

(C) BC (D) bc

Ans: D

Since there is no break statement, all the statement after case’B’ are executed.

Q.13 What will be the output of the following code segment?

main( ) {

char s[10];

strcpy(s, “abc”);

printf(“%d %d”, strlen(s), sizeof(s));

}

(A) 3 10 (B) 3 3

(C) 10 3 (D) 10 10

Ans: A

strlen(s) give the length of the string, that is 3 and sizeof(s) give the size of array s

that is 10.

Q.14 Which of the following is the odd one out?

(A) j = j + 1; (B) j =+ 1;

(C) j++; (D) j += 1;

Ans: B

j=+1 is odd one out as rest all means incrementing the value of variable by 1.

Q.15 Which of the following is true for the statement:

NurseryLand.Nursery.Students = 10;

(A) The structure Students is nested within the structure Nursery.

(B) The structure NurseryLand is nested within the structure Nursery.

(C) The structure Nursery is nested within the structure NurseryLand.

(D) The structure Nursery is nested within the structure Students.

Ans: C

The structure Nursery is nested within the structure NurseryLand.

Q.16 What will be the output of the following code segment, if any?

myfunc ( struct test t) {

strcpy(t.s, “world”);

}

main( ) {

struct test { char s[10]; } t;

strcpy(t.s, “Hello”);

printf(“%s”, t.s);

myfunc(t);

printf(“%s”, t.s);

}

(A) Hello Hello (B) world world

(C) Hello world (D) the program will not compile

Ans: D

The program will not compile because undefined symbol s for myfunc( ) function.

Structure should be defined before the main and the function where it is called.

Q.17 If a function is declared as void fn(int *p), then which of the following statements is

valid to call function fn?

(A) fn(x) where x is defined as int x;

(B) fn(x) where x is defined as int *x;

(C) fn(&x) where x is defined as int *x;

(D) fn(*x) where x is defined as int *x;

Ans: B

Function void fn(int *p) needs pointer to int as argument. When x is defined as int

*x, then x is pointer to integer and not *x.

Q.18 What is the following function computing? Assume a and b are positive integers.

int fn( int a, int b) {

if (b == 0)

return b;

else

return (a * fn(a, b - 1));

}

(A) Output will be 0 always (B) Output will always be b

(C) Computing ab (D) Computing a + b

Ans: A

The output is always be 0 because b is decremented in recursive function fn each time

by 1 till the terminating condition b==0 where it will return 0.

Q.19 What is the output of the following C program?

# include <stdio.h>

main ( )

{

int a, b=0;

static int c [10]={1,2,3,4,5,6,7,8,9,0};

for (a=0; a<10;+ + a)

if ((c[a]%2)= = 0) b+ = c [a];

printf (“%d”, b);

}

(A) 20 (B) 25

(C) 45 (D) 90

Ans: A

printf statement will print b which is sum of the those values from array c which get

divided by 2, that is 2+4+6+8=20.

Q.20 If a, b and c are integer variables with the values a=8, b=3 and c=-5. Then what is the

value of the arithmetic expression:

2 * b + 3 * (a-c)

(A) 45 (B) 6

(C) -16 (D) -1

Ans: A

the value of the arithmetic expression is 45 as 2*3+3*(8—5)=6+3*13=6+39=45

Thank you, Keep Learning