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- Question
What will be the output of the program?
#include<stdio.h> int main() { const c = -11; const int d = 34; printf("%d, %d\n", c, d); return 0; }
Options- A. Error
- B. -11, 34
- C. 11, 34
- D. None of these
- Correct Answer
- -11, 34
ExplanationStep 1: const c = -11; The constant variable 'c' is declared and initialized to value "-11".Step 2: const int d = 34; The constant variable 'd' is declared as an integer and initialized to value '34'.
Step 3: printf("%d, %d\n", c, d); The value of the variable 'c' and 'd' are printed.
Hence the output of the program is -11, 34
Constants problems
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- 1. What will be the output of the program?
#include<stdio.h> int main() { const int x=5; const int *ptrx; ptrx = &x; *ptrx = 10; printf("%d\n", x); return 0; }
Options- A. 5
- B. 10
- C. Error
- D. Garbage value Discuss
Correct Answer: Error
Explanation:
Step 1: const int x=5; The constant variable x is declared as an integer data type and initialized with value '5'.Step 2: const int *ptrx; The constant variable ptrx is declared as an integer pointer.
Step 3: ptrx = &x; The address of the constant variable x is assigned to integer pointer variable ptrx.
Step 4: *ptrx = 10; Here we are indirectly trying to change the value of the constant vaiable x. This will result in an error.
To change the value of const variable x we have to use *(int *)&x = 10;
- 2. What will be the output of the program?
#include<stdio.h> #include<stdlib.h> union employee { char name[15]; int age; float salary; }; const union employee e1; int main() { strcpy(e1.name, "K"); printf("%s %d %f", e1.name, e1.age, e1.salary); return 0; }
Options- A. Error: RValue required
- B. Error: cannot convert from 'const int *' to 'int *const'
- C. Error: LValue required in strcpy
- D. No error Discuss
Correct Answer: No error
Explanation:
The output will be (in 16-bit platform DOS):
K 75 0.000000- 3. What will be the output of the program?
#include<stdio.h> int main() { const char *s = ""; char str[] = "Hello"; s = str; while(*s) printf("%c", *s++); return 0; }
Options- A. Error
- B. H
- C. Hello
- D. Hel Discuss
Correct Answer: Hello
Explanation:
Step 1: const char *s = ""; The constant variable s is declared as an pointer to an array of characters type and initialized with an empty string.Step 2: char str[] = "Hello"; The variable str is declared as an array of charactrers type and initialized with a string "Hello".
Step 3: s = str; The value of the variable str is assigned to the variable s. Therefore str contains the text "Hello".
Step 4: while(*s){ printf("%c", *s++); } Here the while loop got executed untill the value of the variable s is available and it prints the each character of the variable s.
Hence the output of the program is "Hello".
- 4. What will be the output of the program in TurboC?
#include<stdio.h> int fun(int **ptr); int main() { int i=10, j=20; const int *ptr = &i; printf(" i = %5X", ptr); printf(" ptr = %d", *ptr); ptr = &j; printf(" j = %5X", ptr); printf(" ptr = %d", *ptr); return 0; }
Options- A. i= FFE2 ptr=12 j=FFE4 ptr=24
- B. i= FFE4 ptr=10 j=FFE2 ptr=20
- C. i= FFE0 ptr=20 j=FFE1 ptr=30
- D. Garbage value Discuss
Correct Answer: i= FFE4 ptr=10 j=FFE2 ptr=20
- 5. What will be the output of the program?
#include<stdio.h> int main() { const int i=0; printf("%d\n", i++); return 0; }
Options- A. 10
- B. 11
- C. No output
- D. Error: ++needs a value Discuss
Correct Answer: Error: ++needs a value
Explanation:
This program will show an error "Cannot modify a const object".Step 1: const int i=0; The constant variable 'i' is declared as an integer and initialized with value of '0'(zero).
Step 2: printf("%d\n", i++); Here the variable 'i' is increemented by 1(one). This will create an error "Cannot modify a const object".
Because, we cannot modify a const variable.
- 6. What will the function rewind() do?
Options- A. Reposition the file pointer to a character reverse.
- B. Reposition the file pointer stream to end of file.
- C. Reposition the file pointer to begining of that line.
- D. Reposition the file pointer to begining of file. Discuss
Correct Answer: Reposition the file pointer to begining of file.
Explanation:
rewind() takes the file pointer to the beginning of the file. so that the next I/O operation will take place at the beginning of the file.
Example: rewind(FilePointer);- 7. Which standard library function will you use to find the last occurance of a character in a string in C?
Options- A. strnchar()
- B. strchar()
- C. strrchar()
- D. strrchr() Discuss
Correct Answer: strrchr()
Explanation:
strrchr() returns a pointer to the last occurrence of character in a string.Example:
#include <stdio.h> #include <string.h> int main() { char str[30] = "12345678910111213"; printf("The last position of '2' is %d.\n", strrchr(str, '2') - str); return 0; }Output: The last position of '2' is 14.
- 8. Input/output function prototypes and macros are defined in which header file?
Options- A. conio.h
- B. stdlib.h
- C. stdio.h
- D. dos.h Discuss
Correct Answer: stdio.h
Explanation:
stdio.h, which stands for "standard input/output header", is the header in the C standard library that contains macro definitions, constants, and declarations of functions and types used for various standard input and output operations.- 9. 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);- 10. What is stderr?
Options- A. standard error
- B. standard error types
- C. standard error streams
- D. standard error definitions Discuss
Correct Answer: standard error streams
Explanation:
The standard error(stderr) stream is the default destination for error messages and other diagnostic warnings. Like stdout, it is usually also directed to the output device of the standard console (generally, the screen).
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- 1. What will be the output of the program?