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C MCQ Questions and Answers on Arrays and Pointers 1

Study C MCQ Questions and Answers on Arrays, Multidimensional Arrays and Pointers. Easily attend technical interviews after reading these questions.

Go through C Theory Notes on Arrays before studying questions.


1) What is an Array in C language.?
A) A group of elements of same data type.
B) An array contains more than one element
C) Array elements are stored in memory in continuous or contiguous locations.
D) All the above.
Answer [=]
D
2) What is the output of C program.? int main() { float marks[3] = {90.5, 92.5, 96.5}; int a=0; while(a<3) { printf("%.2f,", marks[a]); a++; } }
A) 90.5 92.5 96.5
B) 90.50 92.50 96.50
C) 0.00 0.00 0.00
D) Compiler error
Answer [=]
B
Explanation:

0.2%f prints only two decimal points. It is allowed to use float values with arrays.

3) What is the output of C Program.? int main() { int a[3] = {10,12,14}; a[1]=20; int i=0; while(i<3) { printf("%d ", a[i]); i++; } }
A) 20 12 14
B) 10 20 14
C) 10 12 20
D) Compiler error
Answer [=]
B
Explanation:

a[i] is (i+1) element. So a[1] changes the second element.

4) What is the output of C program.? int main() { int a[3] = {10,12,14}; int i=0; while(i<3) { printf("%d ", i[a]); i++; } }
A) 14 12 10
B) 10 10 10
C) 10 12 14
D) None of the above
Answer [=]
C
Explanation:

a[k] == k[a]. Use any notation to refer to array elements.

5) What is the output of C Program.? int main() { int a[3] = {20,30,40}; a[0]++; int i=0; while(i<3) { printf("%d ", i[a]); i++; } }
A) 20 30 40
B) 41 30 20
C) 21 30 40
D) None of the above
Answer [=]
C
Explanation:

You can use increment and decrement operators on array variables too.

6) What is the output of C program with arrays.? int main() { int a[3] = {20,30,40}; int b[3]; b=a; printf("%d", b[0]); }
A) 20
B) 30
C) address of 0th element.
D) Compiler error
Answer [=]
D
Explanation:

You can assign one array variable to other.

7) What is the output of C Program with arrays and pointers.? int main() { int a[3] = {20,30,40}; int (*p)[3]; p=&a; printf("%d", (*p)[0]); }
A) 20
B) 0
C) address of element 20
D) Compiler error
Answer [=]
A
Explanation:

You can not directly assign one array variable to other. But using an array pointer, you can point to the another array. (*p) parantheses are very important.

8) What is the output of C program with arrays and pointers.? int main() { int a[3] = {20,30,40}; int *p[3]; p=&a; printf("%d", *p[0]); }
A) 20
B) address of element 20
C) Garbage value
D) Compiler error
Answer [=]
D
Explanation:

To point to an array, array pointer declaration should be like (*p)[3] with parantheses. It points to array of 3 elements.

9) What is the output of C program with arrays and pointers.? int main() { int a[3] = {20,30,40}; printf("%d", *(a+1)); }
A) 20
B) 30
C) 40
D) Compiler error
Answer [=]
B
Explanation:

*(a+0) == *a == a[0]. So *(a+1) is element at index 1. Index starts with ZERO.

10) What is an array Base Address in C language.?
A) Base address is the address of 0th index element.
B) An array b[] base address is &b[0]
C) An array b[] base address can be printed with printf("%d", b);
D) All the above
Answer [=]
D
11) What is the output of C Program with arrays and pointers.? void change(int[]); int main() { int a[3] = {20,30,40}; change(a); printf("%d %d", *a, a[0]); } void change(int a[]) { a[0] = 10; }
A) 20 20
B) 10 20
C) 10 10
D) 20 30
Answer [=]
C
Explanation:

Notice that function change() is able to change the value of a[0] of main(). It uses Call By Reference. So changes in called function affected the original values.

12) Choose a correct statement about C language arrays.
A) An array address is the address of first element of array itself.
B) An array size must be declared if not initialized immediately.
C) Array size is the sum of sizes of all elements of the array.
D) All the above
Answer [=]
D
13) An entire array is always passed by ___ to a called function.
A) Call by value
B) Call by reference
C) Address relocation
D) Address restructure
Answer [=]
B
14) What are the Types of Arrays.?
A) int, long, float, double
B) struct, enum
C) char
D) All the above
Answer [=]
D
15) An array Index starts with.?
A) -1
B) 0
C) 1
D) 2
Answer [=]
B
16) Choose a correct statement about C language arrays.
A) An array size can not changed once it is created.
B) Array element value can be changed any number of times
C) To access Nth element of an array students, use students[n-1] as the starting index is 0.
D) All the above
Answer [=]
D
17) What is the output of C Program.? int main() { int a[]; a[4] = {1,2,3,4}; printf("%d", a[0]); }
A) 1
B) 2
C) 4
D) Compiler error
Answer [=]
D
Explanation:

If you do not initialize an array, you must mention ARRAY SIZE.

18) What is the output of C Program.? int main() { int a[] = {1,2,3,4}; int b[4] = {5,6,7,8}; printf("%d,%d", a[0], b[0]); }
A) 1,5
B) 2,6
C) 0 0
D) Compiler error
Answer [=]
A
Explanation:

It is perfectly allowed to skip array size if you are initializing at the same time. a[0] is first element.

int a[] = {1,2,3,4};
19) What is the output of C Program.? int main() { char grade[] = {'A','B','C'}; printf("GRADE=%c, ", *grade); printf("GRADE=%d", grade); }
A) GRADE=some address of array, GRADE=A
B) GRADE=A, GRADE=some address of array
C) GRADE=A, GRADE=A
D) Compiler error
Answer [=]
B
Explanation:

Variable grade = address of first element. *grade is the first element of array i.e grade[0].

20) What is the output of C program.? int main() { char grade[] = {'A','B','C'}; printf("GRADE=%d, ", *grade); printf("GRADE=%d", grade[0]); }
A) A A
B) 65 A
C) 65 65
D) None of the above
Answer [=]
C
Explanation:

*grade == grade[0]. We are printing with %d not with %c. So, ASCII value is printed.