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- Question
Point out the error in the program.
#include<stdio.h> int main() { const int k=7; int *const q=&k; printf("%d", *q); return 0; }
Options- A. Error: RValue required
- B. Error: Lvalue required
- C. Error: cannot convert from 'const int *' to 'int *const'
- D. No error
- Correct Answer
- No error
ExplanationNo error. This will produce 7 as output. - 1. Point out the error in the program.
#include<stdio.h> int main() { const int x; x=128; printf("%d\n", x); return 0; }
Options- A. Error: unknown data type const int
- B. Error: const variable have been initialised when declared.
- C. Error: stack overflow in x
- D. No error Discuss
- 2. Point out the error in the program.
#include<stdio.h> #define MAX 128 int main() { char mybuf[] = "India"; char yourbuf[] = "CURIOUSTAB"; char const *ptr = mybuf; *ptr = 'a'; ptr = yourbuf; return 0; }
Options- A. Error: cannot convert ptr const value
- B. Error: unknown pointer conversion
- C. No error
- D. None of above Discuss
- 3. Point out the error in the program.
#include<stdio.h> const char *fun(); int main() { *fun() = 'A'; return 0; } const char *fun() { return "Hello"; }
Options- A. Error: RValue required
- B. Error: Lvalue required
- C. Error: fun() returns a pointer const character which cannot be modified
- D. No error Discuss
- 4. Point out the error in the program (in Turbo-C).
#include<stdio.h> #define MAX 128 int main() { const int max=128; char array[max]; char string[MAX]; array[0] = string[0] = 'A'; printf("%c %c\n", array[0], string[0]); return 0; }
Options- A. Error: unknown max in declaration/Constant expression required
- B. Error: invalid array string
- C. None of above
- D. No error. It prints A A Discuss
- 5. Point out the error in the program.
#include<stdio.h> const char *fun(); int main() { char *ptr = fun(); return 0; } const char *fun() { return "Hello"; }
Options- A. Error: Lvalue required
- B. Error: cannot convert 'const char *' to 'char *'.
- C. No error and No output
- D. None of above Discuss
- 6. Point out the error in the program.
#include<stdio.h> #define MAX 128 int main() { char mybuf[] = "India"; char yourbuf[] = "CURIOUSTAB"; char *const ptr = mybuf; *ptr = 'a'; ptr = yourbuf; return 0; }
Options- A. Error: unknown pointer conversion
- B. Error: cannot convert ptr const value
- C. No error
- D. None of above Discuss
- 7. Point out the error in the following program.
#include<stdio.h> #include<stdarg.h> fun(...); int main() { fun(3, 7, -11.2, 0.66); return 0; } fun(...) { va_list ptr; int num; va_start(ptr, n); num = va_arg(ptr, int); printf("%d", num); }
Options- A. Error: fun() needs return type
- B. Error: ptr Lvalue required
- C. Error: Invalid declaration of fun(...)
- D. No error Discuss
- 8. Point out the error in the following program.
#include<stdio.h> #include<stdarg.h> int main() { void display(int num, ...); display(4, 12.5, 13.5, 14.5, 44.3); return 0; } void display(int num, ...) { float c; int j; va_list ptr; va_start(ptr, num); for(j=1; j<=num; j++) { c = va_arg(ptr, float); printf("%f", c); } }
Options- A. Error: invalid va_list declaration
- B. Error: var c data type mismatch
- C. No error
- D. No error and Nothing will print Discuss
- 9. Point out the error in the following program.
#include<stdio.h> #include<stdarg.h> int main() { void display(char *s, int num1, int num2, ...); display("Hello", 4, 2, 12.5, 13.5, 14.5, 44.0); return 0; } void display(char *s, int num1, int num2, ...) { double c; char s; va_list ptr; va_start(ptr, s); c = va_arg(ptr, double); printf("%f", c); }
Options- A. Error: invalid arguments in function display()
- B. Error: too many parameters
- C. Error: in va_start(ptr, s);
- D. No error Discuss
- 10. Point out the error if any in the following program (Turbo C).
#include<stdio.h> #include<stdarg.h> void display(int num, ...); int main() { display(4, 'A', 'a', 'b', 'c'); return 0; } void display(int num, ...) { char c; int j; va_list ptr; va_start(ptr, num); for(j=1; j<=num; j++) { c = va_arg(ptr, char); printf("%c", c); } }
Options- A. Error: unknown variable ptr
- B. Error: Lvalue required for parameter
- C. No error and print A a b c
- D. No error and print 4 A a b c Discuss
Constants problems
Search Results
Correct Answer: Error: const variable have been initialised when declared.
Explanation:
Hence Option B is correct
Correct Answer: Error: cannot convert ptr const value
Explanation:
Step 2: char yourbuf[] = "CURIOUSTAB"; The variable yourbuf is declared as an array of characters and initialized with string "CURIOUSTAB".
Step 3: char const *ptr = mybuf; Here, ptr is a constant pointer, which points at a char.
The value at which ptr it points is a constant; it will be an error to modify the pointed character; There will not be any error to modify the pointer itself.
Step 4: *ptr = 'a'; Here, we are changing the value of ptr, this will result in the error "cannot modify a const object".
Correct Answer: Error: fun() returns a pointer const character which cannot be modified
Correct Answer: Error: unknown max in declaration/Constant expression required
Explanation:
Step 2: const int max=128; The constant variable max is declared as an integer data type and it is initialized with value 128.
Step 3: char array[max]; This statement reports an error "constant expression required". Because, we cannot use variable to define the size of array.
To avoid this error, we have to declare the size of an array as static. Eg. char array[10]; or use macro char array[MAX];
Note: The above program will print A A as output in Unix platform.
Correct Answer: No error and No output
Correct Answer: Error: cannot convert ptr const value
Explanation:
Step 2: char yourbuf[] = "CURIOUSTAB"; The variable yourbuf is declared as an array of characters and initialized with string "CURIOUSTAB".
Step 3: char *const ptr = mybuf; Here, ptr is a constant pointer, which points at a char.
The value at which ptr it points is not a constant; it will not be an error to modify the pointed character; There will be an error only to modify the pointer itself.
Step 4: *ptr = 'a'; The value of ptr is assigned to 'a'.
Step 5: ptr = yourbuf; Here, we are changing the pointer itself, this will result in the error "cannot modify a const object".
Correct Answer: Error: Invalid declaration of fun(...)
Explanation:
Correct Answer: Error: var c data type mismatch
Explanation:
Correct Answer: Error: in va_start(ptr, s);
Explanation:
Correct Answer: No error and print A a b c
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