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- Question
What will be the output of the program?
#include<stdio.h> #define str(x) #x #define Xstr(x) str(x) #define oper multiply int main() { char *opername = Xstr(oper); printf("%s\n", opername); return 0; }
Options- A. Error: in macro substitution
- B. Error: invalid reference 'x' in macro
- C. print 'multiply'
- D. No output
- Correct Answer
- print 'multiply'
ExplanationThe macro #define str(x) #x replaces the symbol 'str(x)' with 'x'.The macro #define Xstr(x) str(x) replaces the symbol 'Xstr(x)' with 'str(x)'.
The macro #define oper multiply replaces the symbol 'oper' with 'multiply'.
Step 1: char *opername = Xstr(oper); The varible *opername is declared as an pointer to a character type.
=> Xstr(oper); becomes,
=> Xstr(multiply);
=> str(multiply)
=> char *opername = multiply
Step 2: printf("%s\n", opername); It prints the value of variable opername.
Hence the output of the program is "multiply"
More questions
- 1. Is it necessary that in a function which accepts variable argument list there should be at least be one fixed argument?
Options- A. Yes
- B. No Discuss
Correct Answer: Yes
- 2. Bitwise can be used to generate a random number.
Options- A. Yes
- B. No Discuss
Correct Answer: No
- 3. 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
- 4. 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
- 5. 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.- 6. 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.- 7. Bitwise | can be used to set multiple bits in number.
Options- A. Yes
- B. No Discuss
Correct Answer: Yes
- 8. Bitwise & can be used to check if a bit in number is set or not.
Options- A. True
- B. False Discuss
Correct Answer: True
- 9. A pointer union CANNOT be created
Options- A. Yes
- B. No Discuss
Correct Answer: No
- 10. 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
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