20 Tough C Debugging Questions (MCQ)

What will be the output of the following C code?

int a = 10;

int *p = &a;

*p = *p + 1;

printf("%d", a);

• 10

• 11

• Garbage value

• Compilation error

Identify the error in the following C program:

const int x=1;

x = 10;

• x not initialized

• const variable cannot be modified

• main missing return

• No error

What is the output of this C statement?

printf("%d", printf("C"));

• C

• 1

• C1

• Compilation error

Find the bug in the following C code:

char arr[] = "ABC";

printf("%s", arr);

• Prints ABC

• Missing null terminator

• Compilation error

• Runtime crash

What will be the output of this C code?

int i;

for(i = 0; i < 5; i++);

printf("%d", i);

• 0

• 5

• Infinite loop

• Compilation error

What is wrong in this C code?

int *p;

scanf("%d", p);

• segmentation fault

• Wrong format specifier

• scanf invalid

• No error

What is the output in C?

int x = 3;

printf("%d", x = x + 2 * x);

• 9

• 15

• 6

• Undefined

What does this C code print?

int a[5];

printf("%d", sizeof(a)/sizeof(int));

• Garbage

• Compilation error

• Correct array size

• Runtime error

Identify the issue in this function:

int fun(int x) {

if(x == 0)

return;

return x;

}

• Always returns value

• Compilation error

• Undefined return value

• Infinite loop

What will happen in this C statement?

printf("%d", 10/3);

• Prints 3.33

• Prints 3

• Prints garbage

• Compilation error