Aptitude Test On C-programming (Pointers And Strings) Set -b

1.

Which of the following function is used to find the first occurrence of a given string in another string?

A.

Strnset()
B.

Strchr()
C.

Strrchr()
D.

Strstr()

Correct Answer
D. Strstr()

2.

What would be the equivalent pointer expression for referring the array element a[i][j][k][l]

A.

((((a+i)+j)+k)+l)
B.

*(*(*(*(a+i)+j)+k)+l)
C.

(((a+i)+j)+k+l)
D.

*((a+i)+j+k+l)

Correct Answer
B. *(*(*(*(a+i)+j)+k)+l)

3.

What will be the output of the program ? int main() { char p[] = "%d\n"; p[1] = 'c'; printf(p, 65); return 0; }

A.

A
B.

C
C.

A
D.

65

Correct Answer
C. A

Explanation
char p[] = "%d\n"; The variable p is declared as an array of characters and initialized with string "%d".
p[1] = 'c'; Here, we overwrite the second element of array p by 'c'. So array p becomes "%c".
printf(p, 65); becomes printf("%c", 65);
Therefore it prints the ASCII value of 65. The output is 'A'.

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4.

What will be the output of the program ? int main() { int i; char a[] = "\0"; if(printf("%s", a)) printf("The string is empty\n"); else printf("The string is not empty\n"); return 0; }

A.

No Output
B.

The string is empty
C.

The string is not empty
D.

0

Correct Answer
C. The string is not empty

Explanation
The function printf() returns the number of characters printed on the console.
char a[] = "\0"; The variable a is declared as an array of characters and it initialized with "\0". It denotes that the string is empty.
if(printf("%s", a)) The printf() statement does not print anything, so it returns '0'(zero). Hence the if condition is failed.
In the else part it prints "The string is not empty".

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5.

What will be the output of the program ? int main() { int i=3, *j, k; j = &i; printf("%d\n", i**ji+j); return 0; }

A.

30
B.

27
C.

9
D.

3

Correct Answer
A. 30

Explanation
j=&i implies *j=i;
*j=3
i**j=3*3=9
i**j*i=9*3=27
i**j*i+*j=27+3=30

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6.

What will be the output of the program ? int main() { voidvp; char ch=74, cp="JACK"; int j=65; vp=&ch; printf("%c", (char)vp); vp=&j; printf("%c", (int)vp); vp=cp; printf("%s", (char*)vp+2); return 0; }

A.

JCK
B.

J65K
C.

JACK
D.

JAK

Correct Answer
C. JACK

Explanation
Pointer always store integer value so cp will store the memory address of location where string "jack " is stored.

vp = &ch; Will store address of ch in vp so while we print content in printf it will print asccii value of 74 i.e "J"

vp = &j; It will assign address of j to vp again it will print ascii value of 65 as "A"

vp = cp; In this step cp is pointing to memory locatioon where string jack is stored and we r incrementing it by two so it will point to "C"
from sring "JACK" and since we hava given %S in printf so it will print content from c onward ie "CK"

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7.

What will be the output of the program ? int main() { int i, a[] = {2, 4, 6, 8, 10}; change(a, 5); for(i=0; i<=4; i++) printf("%d, ", a[i]); return 0; } change(int b, int n) { int i; for(i=0; i<n; i++) (b+1) = *(b+i)+5; }

A.

3, 1, -1, -3, -5
B.

7, 9, 11, 13, 15
C.

2, 15, 6, 8, 10
D.

2, 4, 6, 8, 10

Correct Answer
C. 2, 15, 6, 8, 10

Explanation
*(b+1) = *(b+i)+5;
1. i = 0 => *(b+1) ie 4 is replaced by *(b+0)+5 ie 2+5
2. i = 1 => *(b+1) ie 4 is replaced by *(b+1)+5 ie 4+5
3. i = 2 => *(b+1) ie 4 is replaced by *(b+2)+5 ie 6+5
4. i = 3 => *(b+1) ie 4 is replaced by *(b+3)+5 ie 8+5
5. i = 4 => *(b+1) ie 4 is replaced by *(b+4)+5 ie 10+5

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8.

What will be the output of the program ? int main() { char *str; str = "%s"; printf(str, "K\n"); return 0; }

A.

%s
B.

Error
C.

K
D.

No Output

Correct Answer
C. K

Explanation
printf(str, "K\n"); is replaced with printf("%s" , "K\n");
(since str = "%s";)

So it will print K.

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9.

What will be the output of the program ? int main() { printf(5+"Good Morning\n"); return 0; }

A.

Morning
B.

Good Morning
C.

Good
D.

M

Correct Answer
A. Morning

Explanation
printf(5+"Good Morning\n"); It skips the 5 characters and prints the given string.
Hence the output is "Morning"

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10.

What will be the output of the program ? int main() { char str[] = "India\0\is Best\0"; printf("%d\n", strlen(str)); return 0; }

A.

5
B.

10
C.

11
D.

6

Correct Answer
A. 5

Explanation
The function strlen returns the number of characters in the given string.
Therefore, strlen(str) becomes strlen("India") contains 5 characters. A string is a collection of characters terminated by '\0'.
The output of the program is "5"

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11.

What will be the output of the program ? int main() { char str1[] = "Hello"; char str2[] = "Hello"; if(str1 == str2) printf("Equal\n"); else printf("Unequal\n"); return 0; }

A.

Unequal
B.

Equal
C.

Error
D.

None of above

Correct Answer
A. Unequal

Explanation
if(str1 == str2) here the address of str1 and str2 are compared. The addresses of both variables are not same. Hence the if condition is failed.
At the else part it prints "Unequal".

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12.

Trace the output. int main() { char str[] = "basic"; char *s = str; printf("%s ", s++ +3); printf("%s",s); return 0; }

A.

C basic
B.

C c
C.

Ic asic
D.

Asic sic

Correct Answer
C. Ic asic

Explanation
printf("%s ", s++ +3); -> ic since (s++ +3) and s++ is post increment but +3 just print string from 'i'. It ll not increment the pointer to 3.
printf("%s",s); here after incrementing (s++) It ll print ''asic''.

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13.

If the size of integer is 4bytes, What will be the output of the program? int main() { int arr[] = {12, 13, 14, 15, 16}; printf("%d, %d, %d\n", sizeof(arr), sizeof(*arr), sizeof(arr[0])); return 0; }

A.

10, 2, 4
B.

20, 4, 4
C.

20, 2, 2
D.

16, 2, 2

Correct Answer
B. 20, 4, 4

14.

If a variable is a pointer to a structure, then which of the following operator is used to access data members of the structure through the pointer variable?

A.

'.'
B.

'&'
C.

'*'
D.

'->'

Correct Answer
D. '->'

15.

Are the expression ptr++ and ++ptr are same?

A.

True
B.

False

Correct Answer
B. False

Explanation
*ptr++ increments the pointer and not the value,
++*ptr increments the value being pointed by ptr .

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Aptitude Test On C-programming (Pointers And Strings) Set -b

Which of the following function is used to find the first occurrence of a given string in another string?

What would be the equivalent pointer expression for referring the array element a[i][j][k][l]

What will be the output of the program ? int main() { char p[] = "%d\n"; p[1] = 'c'; printf(p, 65); return 0; }

What will be the output of the program ? int main() { int i; char a[] = "\0"; if(printf("%s", a)) printf("The string is empty\n"); else printf("The string is not empty\n"); return 0; }

What will be the output of the program ? int main() { int i=3, *j, k; j = &i; printf("%d\n", i**j*i+*j); return 0; }

What will be the output of the program ? int main() { void*vp; char ch=74, *cp="JACK"; int j=65; vp=&ch; printf("%c", *(char*)vp); vp=&j; printf("%c", *(int*)vp); vp=cp; printf("%s", (char*)vp+2); return 0; }

What will be the output of the program ? int main() { int i, a[] = {2, 4, 6, 8, 10}; change(a, 5); for(i=0; i<=4; i++) printf("%d, ", a[i]); return 0; } change(int *b, int n) { int i; for(i=0; i<n; i++) *(b+1) = *(b+i)+5; }

What will be the output of the program ? int main() { char *str; str = "%s"; printf(str, "K\n"); return 0; }

What will be the output of the program ? int main() { printf(5+"Good Morning\n"); return 0; }

What will be the output of the program ? int main() { char str[] = "India\0\is Best\0"; printf("%d\n", strlen(str)); return 0; }

What will be the output of the program ? int main() { char str1[] = "Hello"; char str2[] = "Hello"; if(str1 == str2) printf("Equal\n"); else printf("Unequal\n"); return 0; }

Trace the output. int main() { char str[] = "basic"; char *s = str; printf("%s ", s++ +3); printf("%s",s); return 0; }

If the size of integer is 4bytes, What will be the output of the program? int main() { int arr[] = {12, 13, 14, 15, 16}; printf("%d, %d, %d\n", sizeof(arr), sizeof(*arr), sizeof(arr[0])); return 0; }

If a variable is a pointer to a structure, then which of the following operator is used to access data members of the structure through the pointer variable?

Are the expression *ptr++ and ++*ptr are same?

What will be the output of the program ? int main() { int i=3, *j, k; j = &i; printf("%d\n", i**ji+j); return 0; }

What will be the output of the program ? int main() { voidvp; char ch=74, cp="JACK"; int j=65; vp=&ch; printf("%c", (char)vp); vp=&j; printf("%c", (int)vp); vp=cp; printf("%s", (char*)vp+2); return 0; }

What will be the output of the program ? int main() { int i, a[] = {2, 4, 6, 8, 10}; change(a, 5); for(i=0; i<=4; i++) printf("%d, ", a[i]); return 0; } change(int b, int n) { int i; for(i=0; i<n; i++) (b+1) = *(b+i)+5; }

Are the expression ptr++ and ++ptr are same?