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- Question
There exists a way to prevent the same file from getting #included twice in the same program.
Options- A. True
- B. False
- Correct Answer
- True
ExplanationTrue, We can prevent the same file from getting included again by using a preprocessor directive called #ifndef (short for "if not defined") to determine whether we've already defined a preprocessor symbol called XSTRING_H. If we have already defined this symbol, the compiler will ignore the rest of the file until it sees a #endif (which in this case is at the end of the file).#ifndef XSTRING_H
#define XSTRING_H defines the same preprocessor symbol,
Finally, the last line of the file, #endif
More questions
- 1. What do the following declaration signify?
int (*pf)();
Options- A. pf is a pointer to function.
- B. pf is a function pointer.
- C. pf is a pointer to a function which return int
- D. pf is a function of pointer variable. Discuss
Correct Answer: pf is a pointer to a function which return int
- 2. What will be the output of the program?
#include<stdio.h> int main() { char str[] = "peace"; char *s = str; printf("%s\n", s++ +3); return 0; }
Options- A. peace
- B. eace
- C. ace
- D. ce Discuss
Correct Answer: ce
- 3. What will be the output of the program?
#include<stdio.h> int main() { int x=12, y=7, z; z = x!=4 || y == 2; printf("z=%d\n", z); return 0; }
Options- A. z=0
- B. z=1
- C. z=4
- D. z=2 Discuss
Correct Answer: z=1
Explanation:
Step 1: int x=12, y=7, z; here variable x, y and z are declared as an integer and variable x and y are initialized to 12, 7 respectively.Step 2: z = x!=4 || y == 2;
becomes z = 12!=4 || 7 == 2;
then z = (condition true) || (condition false); Hence it returns 1. So the value of z=1.Step 3: printf("z=%d\n", z); Hence the output of the program is "z=1".
- 4. What will be the output of the program?
#include<stdio.h> void fun(int); typedef int (*pf) (int, int); int proc(pf, int, int); int main() { int a=3; fun(a); return 0; } void fun(int n) { if(n > 0) { fun(--n); printf("%d,", n); fun(--n); } }
Options- A. 0, 2, 1, 0,
- B. 1, 1, 2, 0,
- C. 0, 1, 0, 2,
- D. 0, 1, 2, 0, Discuss
Correct Answer: 0, 1, 2, 0,
- 5. What will be the output of the program?
#include<stdio.h> int sumdig(int); int main() { int a, b; a = sumdig(123); b = sumdig(123); printf("%d, %d\n", a, b); return 0; } int sumdig(int n) { int s, d; if(n!=0) { d = n%10; n = n/10; s = d+sumdig(n); } else return 0; return s; }
Options- A. 4, 4
- B. 3, 3
- C. 6, 6
- D. 12, 12 Discuss
Correct Answer: 6, 6
- 6. Can you use the fprintf() to display the output on the screen?
Options- A. Yes
- B. No Discuss
Correct Answer: Yes
Explanation:
Do like this fprintf(stdout, "%s %d %f", str, i, a);- 7. What do the following declaration signify?
char *arr[10];
Options- A. arr is a array of 10 character pointers.
- B. arr is a array of function pointer.
- C. arr is a array of characters.
- D. arr is a pointer to array of characters. Discuss
Correct Answer: arr is a array of 10 character pointers.
- 8. The macro va_arg is used to extract an argument from the fixed micro argument list and advance the pointer to the next argument.
Options- A. Yes
- B. No Discuss
Correct Answer: No
- 9. What will be the output of the program?
#include<stdio.h> #define JOIN(s1, s2) printf("%s=%s %s=%s \n", #s1, s1, #s2, s2); int main() { char *str1="India"; char *str2="CURIOUSTAB"; JOIN(str1, str2); return 0; }
Options- A. str1=CuriousTab str2=CURIOUSTAB
- B. str1=India str2=CURIOUSTAB
- C. str1=India str2=CuriousTab
- D. Error: in macro substitution Discuss
Correct Answer: str1=India str2=CURIOUSTAB
- 10. What will be the output of the program?
#include<stdio.h> int main() { int i=3; i = i++; printf("%d\n", i); return 0; }
Options- A. 3
- B. 4
- C. 5
- D. 6 Discuss
Correct Answer: 4
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- 1. What do the following declaration signify?
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