C Programming Questions & Answers

Q.451 Medium Data Types & Variables

What is the range of unsigned int in a 32-bit system?

A 0 to 2^31 - 1

B 0 to 2^32 - 1

C -2^31 to 2^31 - 1

D 0 to 2^16 - 1

Correct Answer: B. 0 to 2^32 - 1

EXPLANATION

Unsigned int uses all 32 bits for magnitude, giving range 0 to 2^32 - 1 (0 to 4,294,967,295).

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Q.452 Medium Data Types & Variables

Which of the following occupies maximum memory in a 64-bit system?

A long int

B long double

C double

D unsigned long long

Correct Answer: B. long double

EXPLANATION

In a 64-bit system, long double typically occupies 16 bytes (128 bits), which is the maximum among these options.

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Q.453 Medium Data Types & Variables

What will be the output of the following code?
int x = 5;
float y = x;
printf("%f", y);

A 5.000000

B Compilation error

C 5

D Garbage value

Correct Answer: A. 5.000000

EXPLANATION

Implicit type conversion occurs from int to float. The value 5 is converted to 5.0 and printed as 5.000000 with %f format specifier.

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Q.454 Medium Basics & Syntax

What is the output of this code?
#include
int main() {
int a = 5, b = 10;
a = a ^ b;
b = a ^ b;
a = a ^ b;
printf("%d %d", a, b);
return 0;
}

A 5 10

B 10 5

C 0 0

D 10 10

Correct Answer: B. 10 5

EXPLANATION

This is a classic XOR swap algorithm. After three XOR operations, a and b exchange their values. Result: a=10, b=5.

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Q.455 Medium Basics & Syntax

What will be printed by the following code?
#include
int main() {
int arr[5] = {1, 2, 3, 4, 5};
int *p = arr;
printf("%d %d", *(p+2), arr[2]);
return 0;
}

A 3 3

B 2 4

C 4 3

D 3 4

Correct Answer: A. 3 3

EXPLANATION

*(p+2) accesses the element at index 2 (value 3), and arr[2] also accesses index 2 (value 3). Both print 3.

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Q.456 Medium Basics & Syntax

Consider the following code:
int x = 5;
int *ptr = &x;
int **pptr = &ptr;
printf("%d", **pptr);
What is the output?

A 5

B Address of x

C Address of ptr

D Compilation Error

Correct Answer: A. 5

EXPLANATION

pptr is a pointer to pointer. **pptr dereferences twice: first to get ptr, then to get x's value which is 5.

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Q.457 Medium Basics & Syntax

Which of the following about register variables is TRUE?

A They must be initialized

B They are faster to access than normal variables

C They cannot be pointers

D They are stored in RAM

Correct Answer: B. They are faster to access than normal variables

EXPLANATION

register keyword suggests the compiler to store the variable in CPU register for faster access. Modern compilers often ignore this hint. You cannot take address of register variables.

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Q.458 Medium Basics & Syntax

What does the 'volatile' keyword in C indicate?

A Variable value can change unexpectedly

B Variable is constant

C Variable is local

D Variable must be initialized

Correct Answer: A. Variable value can change unexpectedly

EXPLANATION

volatile tells the compiler that a variable's value can change unexpectedly (e.g., in hardware registers or interrupt handlers), so it should not optimize away repeated reads.

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Q.459 Medium Basics & Syntax

What is the output of: printf("%d %d", 10 % 3, 10 / 3);

A 3 3

B 1 3

C 3 1

D 10 10

Correct Answer: B. 1 3

EXPLANATION

10 % 3 = 1 (remainder), 10 / 3 = 3 (integer division). Output is '1 3'.

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Q.460 Medium Basics & Syntax

Which of the following is correct about static variables in C?

A They are destroyed after function returns

B They retain their value between function calls

C They cannot be used in functions

D They are global by default

Correct Answer: B. They retain their value between function calls

EXPLANATION

Static variables retain their value between function calls and are initialized only once. They persist for the lifetime of the program.

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