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- Question
Assuming a integer 2-bytes, What will be the output of the program?
#include<stdio.h> int main() { printf("%x\n", -1<<3); return 0; }
Options- A. ffff
- B. fff8
- C. 0
- D. -1
- Correct Answer
- fff8
ExplanationThe system will treat negative numbers in 2's complement method.
Example:
Assume the size of int is 2-bytes(16 bits). The integer value 1 is represented as given below:
Binary of 1: 00000000 00000001 (this is for positive value of 1)
1's complement of binary 1: 11111111 11111110
2's complement of binary 1: 11111111 11111111
Thy system will store '11111111 11111111' in memory to represent '-1'.
If we do left shift (3 bits) on 11111111 11111111 it will become as given below:
11111111 11111111 ---(left shift 3 times)---> 11111111 11111000.
So, 11111111 11111000 ---(binary to hex)---> FF F8. (Required Answer)
Note:
How is the negative number obtained from 2's complement value?
As stated above, -1 is represented as '11111111 11111111' in memory.
So, the system will take 2's complement of '11111111 11111111' to the get the original negative value back.
Example:
Bit Representation of -1: 11111111 11111111
Since the left most bit is 1, it is a negative number. Then the value is
1's complement: 00000000 00000000
2's complement: 00000000 00000001 (Add 1 to the above result)
Therefore, '00000000 00000001' = 1 and the sign is negative.
Hence the value is -1.
More questions
- 1. Which of the following statements correct about k used in the below statement?
char ****k;
Options- A. k is a pointer to a pointer to a pointer to a char
- B. k is a pointer to a pointer to a pointer to a pointer to a char
- C. k is a pointer to a char pointer
- D. k is a pointer to a pointer to a char Discuss
Correct Answer: k is a pointer to a pointer to a pointer to a pointer to a char
- 2. What will be the output of the program?
#include<stdio.h> void fun(void *p); int i; int main() { void *vptr; vptr = &i; fun(vptr); return 0; } void fun(void *p) { int **q; q = (int**)&p; printf("%d\n", **q); }
Options- A. Error: cannot convert from void** to int**
- B. Garbage value
- C. 0
- D. No output Discuss
Correct Answer: 0
- 3. What will be the output of the program?
#include<stdio.h> #include<string.h> int main() { static char s[] = "Hello!"; printf("%d\n", *(s+strlen(s))); return 0; }
Options- A. 8
- B. 0
- C. 16
- D. Error Discuss
Correct Answer: 0
- 4. What will be the output of the program?
#include<stdio.h> int main() { int i=4, j=8; printf("%d, %d, %d\n", i|j&j|i, i|j&&j|i, i^j); return 0; }
Options- A. 4, 8, 0
- B. 1, 2, 1
- C. 12, 1, 12
- D. 0, 0, 0 Discuss
Correct Answer: 12, 1, 12
- 5. What will you do to treat the constant 3.14 as a float?
Options- A. use float(3.14f)
- B. use 3.14f
- C. use f(3.14)
- D. use (f)(3.14) Discuss
Correct Answer: use 3.14f
Explanation:
Given 3.14 is a double constant.
To specify 3.14 as float, we have to add f to the 3.14. (i.e 3.14f)
- 6. What will be the output of the program if value 25 given to scanf()?
#include<stdio.h> int main() { int i; printf("%d\n", scanf("%d", &i)); return 0; }
Options- A. 25
- B. 2
- C. 1
- D. 5 Discuss
Correct Answer: 1
Explanation:
The scanf function returns the number of input is given.printf("%d\n", scanf("%d", &i)); The scanf function returns the value 1(one).
Therefore, the output of the program is '1'.
- 7. In the statement expression1 >> expression2. if expression1 is a signed integer with its leftmost bit set to 1 then on right shifting it the result of the statement will vary from computer to computer
Options- A. True
- B. False Discuss
Correct Answer: True
- 8. What do the following declaration signify?
int *ptr[30];
Options- A. ptr is a pointer to an array of 30 integer pointers.
- B. ptr is a array of 30 pointers to integers.
- C. ptr is a array of 30 integer pointers.
- D. ptr is a array 30 pointers. Discuss
Correct Answer: ptr is a array of 30 pointers to integers.
- 9. Range of float id -2.25e+308 to 2.25e+308
Options- A. True
- B. False Discuss
Correct Answer: False
Explanation:
False, The range of float is -3.4e+38 to 3.4e+38.- 10. What will be the output of the program (in Turbo C under DOS)?
#include<stdio.h> int main() { char huge *near *far *ptr1; char near *far *huge *ptr2; char far *huge *near *ptr3; printf("%d, %d, %d\n", sizeof(ptr1), sizeof(ptr2), sizeof(ptr3)); return 0; }
Options- A. 4, 4, 8
- B. 2, 4, 4
- C. 4, 4, 2
- D. 2, 4, 8 Discuss
Correct Answer: 4, 4, 2
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- 1. Which of the following statements correct about k used in the below statement?