What will be the output of this code? #include <stdio.h> int main() { int i = 5; printf("%d %d %d", i, i++, ++i); return 0; }

• 5 5 7
• 7 6 7
• 5 6 7
• Undefined Behavior

Answer explanation

Undefined order of evaluation leads to undefined behavior.

What is the size of sizeof('A') in a 64-bit GCC compiler?

• 1
• 2
• 4
• 8

Answer explanation

Character constants are of type int, hence 4 bytes.

Which keyword is used to declare a variable that retains its value across function calls?

• auto
• extern
• static
• register

Answer explanation

static retains value across function calls.

What is returned by fopen() if it fails to open a file?

• -1
• 0
• NULL
• EOF

Answer explanation

fopen returns NULL if it fails.

What will the following code print? #include <stdio.h> int main() { char *p = "Hello"; *p = 'M'; printf("%s", p); }

• Hello
• Mello
• Compiler Error
• Undefined Behavior

Answer explanation

Modifying string literal is undefined behavior.

Which of the following is not a valid storage class in C?

• auto
• static
• dynamic
• register

Answer explanation

dynamic is not a C storage class.

What is the output of: printf("%d", printf("Hi"));

• Hi1
• Hi2
• Hi0
• Error

Answer explanation

printf prints 'Hi' and returns 2, so output is 'Hi2'.

Which of the following functions is used to allocate memory that is initialized to zero?

• malloc()
• calloc()
• realloc()
• free()

Answer explanation

calloc initializes allocated memory to zero.

What is the output of the code? int main() { char arr[] = "abcd"; char *p = arr; printf("%c", *++p); }

• a
• b
• c
• d

Answer explanation

*++p moves pointer to 'b'.

Which of the following functions compares two strings in C?

• strcpy()
• strcmp()
• strcat()
• strrev()

Answer explanation

strcmp compares strings.