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- Question
What will be the output of the program?
#include<stdio.h> int main() { struct value { int bit1:1; int bit3:4; int bit4:4; }bit={1, 2, 13}; printf("%d, %d, %d\n", bit.bit1, bit.bit3, bit.bit4); return 0; }
Options- A. 1, 2, 13
- B. 1, 4, 4
- C. -1, 2, -3
- D. -1, -2, -13
- Correct Answer
- -1, 2, -3
ExplanationNote the below statement inside the struct:
int bit1:1; --> 'int' indicates that it is a SIGNED integer.
For signed integers the leftmost bit will be taken for +/- sign.
If you store 1 in 1-bit field:
The left most bit is 1, so the system will treat the value as negative number.
The 2's complement method is used by the system to handle the negative values.
Therefore, the data stored is 1. The 2's complement of 1 is also 1 (negative).
Therefore -1 is printed.
If you store 2 in 4-bits field:
Binary 2: 0010 (left most bit is 0, so system will treat it as positive value)
0010 is 2
Therefore 2 is printed.
If you store 13 in 4-bits field:
Binary 13: 1101 (left most bit is 1, so system will treat it as negative value)
Find 2's complement of 1101:
1's complement of 1101 : 0010
2's complement of 1101 : 0011 (Add 1 to the result of 1's complement)
0011 is 3 (but negative value)
Therefore -3 is printed.
More questions
- 1. A function that receives variable number of arguments should use va_arg() to extract the last argument from the variable argument list.
Options- A. True
- B. False Discuss
Correct Answer: False
- 2. Bitwise & can be used to check if more than one bit in a number is on.
Options- A. True
- B. False Discuss
Correct Answer: True
- 3. The preprocessor can trap simple errors like missing declarations, nested comments or mismatch of braces.
Options- A. True
- B. False Discuss
Correct Answer: False
Explanation:
False, the preprocessor cannot trap the errors, it only replaces the macro with the given expression. But the compiler will detect errors.- 4. It is necessary that a header files should have a .h extension?
Options- A. Yes
- B. No Discuss
Correct Answer: No
Explanation:
No, the header files have any kind of extension.- 5. Bitwise | can be used to set multiple bits in number.
Options- A. Yes
- B. No Discuss
Correct Answer: Yes
- 6. Bitwise & can be used to check if a bit in number is set or not.
Options- A. True
- B. False Discuss
Correct Answer: True
- 7. A pointer union CANNOT be created
Options- A. Yes
- B. No Discuss
Correct Answer: No
- 8. What will be the output of the program?
#include<stdio.h> #include<stdlib.h> int main() { union test { int i; float f; char c; }; union test *t; t = (union test *)malloc(sizeof(union test)); t->f = 10.10f; printf("%f", t->f); return 0; }
Options- A. 10
- B. Garbage value
- C. 10.100000
- D. Error Discuss
Correct Answer: 10.100000
- 9. What will be the output of the program?
#include<stdio.h> int main() { int x=4, y, z; y = --x; z = x--; printf("%d, %d, %d\n", x, y, z); return 0; }
Options- A. 4, 3, 3
- B. 4, 3, 2
- C. 3, 3, 2
- D. 2, 3, 3 Discuss
Correct Answer: 2, 3, 3
Explanation:
Step 1: int x=4, y, z; here variable x, y, z are declared as an integer type and variable x is initialized to 4.
Step 2: y = --x; becomes y = 3; because (--x) is pre-decrement operator.
Step 3: z = x--; becomes z = 3;. In the next step variable x becomes 2, because (x--) is post-decrement operator.
Step 4: printf("%d, %d, %d\n", x, y, z); Hence it prints "2, 3, 3".
- 10. Functions cannot return a floating point number
Options- A. Yes
- B. No Discuss
Correct Answer: No
Explanation:
A function can return floating point value.Example:
#include <stdio.h> float sub(float, float); /* Function prototype */ int main() { float a = 4.5, b = 3.2, c; c = sub(a, b); printf("c = %f\n", c); return 0; } float sub(float a, float b) { return (a - b); }Output:
c = 1.300000
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