Pointers
Question 1 |
Consider the following ANSI C program
#include<stdio.h>
int main() {
int arr[4][5];
int i, j;
for (i=0; i<4; i++){
for (j=0; j<5; j++){
arr[i][j] = 10*i + j;
}
}
printf (“%d”, *(arr[1] + 9));
return 0;
}
What is the output of the above program?
#include<stdio.h>
int main() {
int arr[4][5];
int i, j;
for (i=0; i<4; i++){
for (j=0; j<5; j++){
arr[i][j] = 10*i + j;
}
}
printf (“%d”, *(arr[1] + 9));
return 0;
}
What is the output of the above program?
14 | |
30 | |
24 | |
20 |
Question 1 Explanation:
arr[4][5]
Question 2 |
Faster access to non-local variables is achieved using an array of pointers to activation records called a
stack | |
heap | |
display | |
activation tree |
Question 2 Explanation:
Properties of displays:
→ Use a pointer array to store the activation records along the static chain.
→ Fast access for non-local variables but may be complicated to maintain.
→ Use a pointer array to store the activation records along the static chain.
→ Fast access for non-local variables but may be complicated to maintain.
Question 3 |
Consider the following three C functions:
[PI] int*g(void)
{
int x = 10;
return(&x);
}
[P2] int*g(void)
{
int*px;
*px = 10;
return px;
}
[P3] int*g(void)
{
int*px;
px = (int *) malloc(sizeof(int));
*px = 10;
return px;
}
Which of the above three functions are likely to cause problems with pointers?
Only P3 | |
Only P1 and P3 | |
Only P1 and P2 | |
P1, P2 and P3 |
Question 3 Explanation:
[P1] → May cause error because the function is returning the address of locally declared variable.
[P2] → It will cause problem because px is in int pointer that is not assigned with any address and we are doing dereferencing.
[P3] → It will work because memory will be stored in px that can be use further. Once function execution completes this will exist in Heap.
[P2] → It will cause problem because px is in int pointer that is not assigned with any address and we are doing dereferencing.
[P3] → It will work because memory will be stored in px that can be use further. Once function execution completes this will exist in Heap.
Question 4 |
What is printed by the following ANSI C program?
#include
int main(int argc, char *argv[])
{
int x = 1, z[2] = {10, 11};
int *p = NULL;
p = &x;
*p = 10;
p = &z[1];
*(&z[0] + 1) += 3;
printf("%d, %d, %d\n", x, z[0], z[1]);
return 0;
}
#include
int main(int argc, char *argv[])
{
int x = 1, z[2] = {10, 11};
int *p = NULL;
p = &x;
*p = 10;
p = &z[1];
*(&z[0] + 1) += 3;
printf("%d, %d, %d\n", x, z[0], z[1]);
return 0;
}
1, 10, 11 | |
1, 10, 14 | |
10, 14, 11 | |
10, 10, 14 |
Question 4 Explanation:
Question 5 |
Which of the following declares ‘pf’ as a pointer to a function, which returns an integer quantity and requires two integer arguments ?
int *pf(int, int); | |
int (*pf)(int, int); | |
(int *) pf(int, int); | |
int ( int *pf(int, int)); |
Question 5 Explanation:
int (*pf)(int, int) , Here ‘pf’ declares as a pointer to a function, which returns an integer quantity and requires two integer arguments
Question 6 |
Which of the following statements is TRUE for the function prototype declaration given below?
Int *(*P)(char *Q[]);
P is a function that accepts an argument which is a character array and returns a pointer to an integer quantity. | |
P is a function that accepts an argument which is a pointer to a character array and returns a pointer to an integer quantity. | |
P is a pointer to a function that accepts an argument which is an array of character pointers, and returns a pointer to an integer quantity. | |
P is a pointer to function that accepts an argument which is a character array and returns a pointer to an integer quantity . |
Question 6 Explanation:
P is a pointer to a function that accepts an argument which is an array of character pointers, and returns a pointer to an integer quantity.
Question 7 |
Which of the following statements about pointers in C are TRUE.
(A) Pointers can be used to access array elements
(B) Pointers can store the address of another pointer
(C) Pointers are automatically deferenced in expression
(D) Pointers cannot be used to access structure members
Choose the correct answer from the options given below :
(A) Pointers can be used to access array elements
(B) Pointers can store the address of another pointer
(C) Pointers are automatically deferenced in expression
(D) Pointers cannot be used to access structure members
Choose the correct answer from the options given below :
(A) and (C) only
| |
(A) and (B) Only
| |
(B) and (C) Only | |
(C) and (D) Only |
Question 7 Explanation:
The correct answer is (A) and (B) only.
There are 7 questions to complete.