C questions in placement tests and university exams are rarely about syntax alone. Most of what you will find here is output prediction, pointer arithmetic, arrays and strings, structures and unions, storage classes, recursion, and file handling. The explanations walk through memory behaviour step by step, which is usually where the confusion sits rather than in the code itself.
In C, which of the following statements about pointers is TRUE?
Answer: B
A pointer stores the memory address of a variable. Pointer size depends on the system architecture, not always 4 bytes.
Q.22Medium
What will be the output of the following code? #include <stdio.h> int main() { int x = 10, y = 20; int *p = &x, *q = &y; *p = *q; printf("%d %d", x, y); return 0; }
Answer: B
*p = *q assigns the value of y (20) to x through the pointer p. So x becomes 20, y remains 20.
Q.23Medium
What is the output of the following code? #include <stdio.h> int main() { int a = 5, b = 10; a = b++; printf("%d %d", a, b); return 0; }
Answer: B
b++ returns the current value of b (10) before incrementing, so a = 10. Then b increments to 11.
Q.24Medium
Which of the following is NOT a valid data type modifier in C?
Answer: C
The 'long' modifier cannot be used with 'float'. You can only use 'double' or 'long double' for longer floating-point types.
Q.25Easy
What will be printed by the following code? #include <stdio.h> int main() { char str[] = "Hello"; printf("%c", str[1]); return 0; }
What is the main difference between #define and const in C?
Answer: C
#define is a preprocessor directive replaced before compilation, while const creates an actual variable. const occupies memory; #define does not.
Q.27Hard
Which of the following correctly declares a function pointer?
Answer: B
Function pointers require parentheses around the pointer name: int (*func)(). Option D declares a function returning int pointer, not a function pointer.
Q.28Medium
Which memory segment stores global variables in C?
Answer: C
Global variables are stored in the data segment (also called BSS segment for uninitialized globals). Local variables use the stack.
Q.29Easy
What is the output of the following code? #include <stdio.h> int main() { char c = 'A'; printf("%d", c); return 0; }
Answer: A
The %d format specifier prints the ASCII value of the character. 'A' has ASCII value 65.
Q.30Hard
What will be the output of the following code? #include <stdio.h> int main() { int x = 5; int y = ++x * ++x; printf("%d", y); return 0; }
Answer: C
The expression ++x * ++x modifies x twice without an intervening sequence point, causing undefined behavior.
Q.31Medium
In C, what is the purpose of the 'static' keyword when used with a global variable?
Answer: A
When 'static' is used with a global variable, it restricts its scope to the current file (internal linkage), making it not accessible from other files.
Q.32Easy
Which of the following is the correct syntax to declare a pointer to an integer in C?
Answer: A
In C, a pointer to an integer is declared using 'int *ptr;' where '*' indicates pointer declaration.
Q.33Easy
What is the size of 'char' data type in C?
Answer: C
The 'char' data type in C occupies 1 byte of memory and can store a single character.
Q.34Easy
Which of the following variable names is valid in C?
Answer: C
Variable names in C must start with a letter or underscore, followed by alphanumeric characters or underscores. '_variable123' is valid, while '2variable' starts with digit, 'var-iable' has hyphen, and 'var iable' has space.
Q.35Easy
What is the default return type of the main() function in C?
Answer: B
The main() function implicitly returns int type, which indicates the program's exit status (0 for success, non-zero for failure).
Q.36Easy
Which escape sequence is used to print a newline character in C?
Answer: B
The escape sequence \n represents a newline character that moves the cursor to the next line.
Q.37Medium
What is the range of values for 'signed char' in C (assuming 8-bit char)?
Answer: B
A signed char is 1 byte (8 bits) and can represent values from -128 to 127 using two's complement representation.
Q.38Medium
What will be the output of the expression: 25 in C (considering integer division)?
Answer: C
In C, when both operands are integers, division performs integer division, discarding the fractional part. 25 = 2.
Q.39Medium
Which of the following correctly represents a string literal in C?
Answer: B
Strings in C are represented using double quotes and stored in character arrays. Single quotes are for single characters.
Q.40Medium
What is the primary purpose of the 'volatile' keyword in C?
Answer: B
The 'volatile' keyword tells the compiler not to optimize accesses to a variable, as its value can change from external sources (hardware, signals, etc.).
