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.
Which of the following is NOT a fundamental data type in C?
Answer: C
C has 5 fundamental data types: int, float, double, char, and void. 'string' is not a fundamental type; it's created using char arrays.
Q.2Easy
What is the size of an 'int' variable in a 32-bit system?
Answer: B
In a 32-bit system, an int is typically 4 bytes (32 bits). However, the C standard only guarantees it's at least 2 bytes, so technically it's compiler-dependent. But in practice, 4 bytes is standard.
Q.3Easy
Which variable declaration is correct in C?
Answer: C
Variable names must start with a letter or underscore, followed by letters, digits, or underscores. Option C follows this rule correctly.
Q.4Easy
Which keyword is used to declare a variable that cannot be modified?
Answer: B
'const' keyword makes a variable constant and immutable after initialization.
Q.5Easy
Which of the following is a derived data type in C?
Answer: B
Derived data types are created from fundamental types. Arrays, pointers, structures, and unions are derived types.
Q.6Easy
How many bits are used to store a 'short int' in a standard C environment?
Answer: B
Standard C guarantees short int is at least 16 bits (2 bytes). Most systems use exactly 16 bits.
Q.7Easy
What is the range of values for a signed char in C?
Answer: B
A signed char occupies 1 byte (8 bits). With sign bit, it ranges from -128 to 127 (2^7 to 2^7-1).
Q.8Easy
Which keyword is used to modify a variable so that it cannot be changed?
Answer: B
The const keyword makes a variable read-only after initialization. Its value cannot be modified during program execution.
Q.9Easy
What is the size of the double data type in most 64-bit systems?
Answer: B
In standard C on 64-bit systems, double occupies 8 bytes and can store values with approximately 15-17 significant digits.
Q.10Easy
Which of the following variable names is INVALID in C?
Answer: C
Variable names cannot start with a digit in C. Valid names must begin with a letter (a-z, A-Z) or underscore (_).
Q.11Easy
What will be the result of sizeof(int) on a typical 32-bit system?
Answer: B
On 32-bit systems, int is typically 4 bytes (32 bits). However, the exact size is implementation-defined per C standard.
Q.12Easy
What is the default data type of a floating-point constant in C?
Answer: B
In C, floating-point constants like 3.14 are treated as double by default. To specify float, you need to use 3.14f suffix.
Q.13Easy
What is the range of unsigned char in C?
Answer: B
unsigned char is 1 byte (8 bits) without sign bit, giving range 0 to 2^8-1 = 0 to 255.
Q.14Easy
What is the scope of a variable declared inside a function block?
Answer: C
Variables declared inside a block (including function blocks) have block scope and are accessible only within that block.
Q.15Easy
Which of the following is a storage class in C?
Answer: C
The storage classes in C are: auto, register, static, and extern. 'static' is one of them.
Q.16Easy
What is the difference between initialization and assignment in C?
Answer: B
Initialization assigns a value when the variable is declared (int x = 5;). Assignment changes the value later (x = 10;).
Q.17Easy
What is the size of a 'float' data type in C on most 32-bit systems?
Answer: B
On most 32-bit systems, float occupies 4 bytes (32 bits) of memory according to IEEE 754 standard.
Q.18Easy
What is the range of 'signed char' in C?
Answer: B
Signed char uses 8 bits with one bit for sign, giving range -128 to 127 (2^7 to 2^7-1).
Q.19Easy
What happens if you assign a double value to an int variable without casting?
Answer: B
Implicit conversion truncates decimal part. int x = 3.7; results in x=3 with no error.
Q.20Easy
What is the size of the 'char' data type in C on most modern systems?
Answer: A
The 'char' data type occupies 1 byte (8 bits) of memory on virtually all modern C systems, as per the C standard.
