C Programming MCQs with answers Page - 1

The compilation of a C program goes through several stages:

Preprocessing:

• The preprocessor handles directives like #include, #define, and #ifdef.
• It replaces macros, expands header files, and processes conditional compilation.

Compilation:

• Converts the preprocessed C code into assembly language.

Assembly:

• Translates the assembly code into machine code (object file).

Linking:

• Combines multiple object files and libraries into a single executable.

Since preprocessing is the first stage in this sequence, the correct answer is (C) Preprocessing.

In C language, getchar() is a standard library function used to read a single character from the standard input (keyboard).

Usage of getchar()

#include <stdio.h>



int main() {

    char ch;

    printf("Enter a character: ");

    ch = getchar();  // Reads a single character

    printf("You entered: %c\n", ch);

    return 0;

}

Why Not the Other Options?

• (A) putchar() → Outputs (prints) a single character, does not read.
• (B) printf() → Prints formatted output, does not read characters.
• (D) write() → A low-level system call, not a standard library function for character input.

Thus, (C) getchar() is the correct answer!

In the ASCII character set, each character is assigned a unique integer value.

• The character 'A' has an ASCII value of 65.
• Similarly:
  • 'B' = 66
  • 'C' = 67
  • 'a' (lowercase) = 97

Example in C:

#include <stdio.h>



int main() {

    printf("ASCII value of 'A' is: %d\n", 'A');  // Output: 65

    return 0;

}

Why Not the Other Options?

• (A) 1 → Incorrect, as 'A' corresponds to 65 in ASCII.
• (C) 101 → Incorrect, 101 is the ASCII value of 'e'.
• (D) 20 → Incorrect, 20 is not the ASCII value of 'A'.

Thus, the correct answer is (B) 65.

There is a mistake in the code:
#include <studio.h> should be #include <stdio.h>.

Now, let's analyze the corrected code:

#include <stdio.h>  // Corrected header file



int main() {

    int a = 40, b = 50, c = 10, x;

    x = a < b < c;  // Evaluating this expression

    printf("%d\n", x);

    return 0;

}

Step-by-Step Execution:

The key part is this expression:

x = a < b < c;

which is equivalent to:

x = (a < b) < c;

First comparison:

• a < b → 40 < 50 → True (1)

Second comparison:

• Now, we evaluate 1 < c → 1 < 10 → True (1)

Thus, x = 1, and the output is:

1

Correct Answer:

(B) 1 ✅

In C, the range of a signed char variable depends on its storage size, which is 1 byte (8 bits).

• The most significant bit (MSB) is used for the sign (0 for positive, 1 for negative).
• The remaining 7 bits store the value.

Correct Answer:

(B) -128 to 127 ✅

In the given C program:

#include <stdio.h>

int main ( )

{

      float floatvalue = 8.25;

      printf ("%d\n", (int) floatvalue);

      return 0;

}

1. floatvalue is initialized as 8.25 (a float type).
2. (int) floatvalue typecasts 8.25 to an int, which removes the decimal part, resulting in 8.
3. The %d format specifier is used in printf(), which expects an int. Since we are explicitly typecasting floatvalue to int, it prints 8.

Correct Output:

(D) 8 ✅

The valid range of long double depends on the system and compiler, but typically for most modern compilers (like GCC with x86-64 architecture using 80-bit extended precision), the range is:

Correct Answer:

✅ (A) 3.4E-4932 to 1.1E+4932

Explanation:

• long double in most modern systems uses 80-bit extended precision (sometimes 128-bit on specific architectures).
• Its range is significantly larger than double, which has a range of approximately 1.7E-308 to 1.7E+308.
• The values 3.4E-4932 to 1.1E+4932 match the standard long double range on many x86-64 systems.

Would you like to confirm the range for a specific compiler (like GCC, Clang, or MSVC)?

• In C language, implicit typing depends on the context.
• The value 35.29 is a double literal by default in C.
• However, the datatype of n will depend on how it's declared.

Cases:

1. If n is declared as float → n = 35.29; will store it as a single-precision floating-point number.
2. If n is declared as double → It remains a double (default for floating-point literals in C).
3. If n is declared as long double → The value will be promoted to long double (extended precision, depending on the system).

The sizeof() operator returns the size (in bytes) of a data type or expression. Let's analyze each argument inside printf:

Breakdown of sizeof() calls:

1. sizeof(2.19f) → 2.19f is a float, which typically takes 4 bytes.
2. sizeof(2.19) → 2.19 is a double (default type for floating-point literals in C), which typically takes 8 bytes.
3. sizeof(2.19l) → 2.19l (or 2.19L) is a long double, which usually takes 10 bytes on most systems (but may be 12 or 16 bytes on some architectures).

Thus, the output is 4 8 10.

The printf() function is used to print a floating-point number in different formats:

• %f → Prints the number in decimal notation (default floating-point format).
• %e → Prints the number in scientific notation (lowercase 'e').
• %E → Prints the number in scientific notation (uppercase 'E').

Breakdown of Output:

For n = 5.375:

1. %f → 5.375000 (default 6 decimal places)
2. %e → 5.375000e+000
3. %E → 5.375000E+000

Thus, the output is:

5.375000 5.375000e+000 5.375000E+000