Basic data types, also known as primary or fundamental data types, are the core building blocks for storing data in C. They are predefined by the language and are used to represent single values like numbers and characters.

int (Integer)

The int data type is used to store whole numbers, both positive and negative, without any decimal part.

·         Purpose: Storing integer values like age, roll numbers, or counts.

·         Size: Typically 4 bytes (32 bits), but this can vary by system.

·         Format Specifier: %d

Example:

C

#include <stdio.h>

int main() {

    // Declaring an integer variable

    int year = 2025;

    // Declaring another integer for a negative value

    int temperature = -5;

    printf("The current year is: %d\n", year);

    printf("The temperature is: %d degrees Celsius\n", temperature);

    return 0;

}

char (Character)

The char data type is used to store a single character, such as a letter, a digit, or a special symbol. The character must be enclosed in single quotes ('). Internally, characters are stored as integers based on the ASCII character set.

·         Purpose: Storing single characters like a grade, an initial, or a symbol.

·         Size: 1 byte.

·         Format Specifier: %c

Example:

C

#include <stdio.h>

int main() {

    char grade = 'A';

    char symbol = '$';

    printf("The student's grade is: %c\n", grade);

    printf("The currency symbol is: %c\n", symbol);

    // Demonstrating the integer nature of char

    printf("The ASCII value of '%c' is %d\n", grade, grade);

    return 0;

}

float and double (Floating-Point)

float and double are used to store real numbers (numbers with a decimal point). The main difference is their precision and size.

·         float: For single-precision floating-point numbers. It has about 6-7 digits of precision.

o    Size: 4 bytes.

o    Format Specifier: %f

·         double: For double-precision floating-point numbers. It offers much higher precision (about 15-16 digits) and is generally preferred for real-number calculations.

o    Size: 8 bytes.

o    Format Specifier: %lf

Example:

C

#include <stdio.h>

int main() {

    // Use 'f' suffix for float literals

    float price = 499.99f; 

    double pi = 3.1415926535;

    printf("The price is: %f\n", price);

    printf("The value of PI is: %lf\n", pi);

    return 0;

}

Type Modifiers

These keywords are used to modify the properties (like size or sign) of the basic integer and character types.

·         short, long: Affect the size of the data type. long int can store larger integers than a plain int.

·         signed, unsigned: Determine if the variable can hold negative values. By default, types are signed. An unsigned int can only store non-negative values (0 and positive), allowing it to hold a larger maximum positive value compared to a signed int of the same size.

The void Type

The void type is a special-purpose type that has no value. It is primarily used in two scenarios:

1.   Function Return Type: To specify that a function does not return any value.

C

                            void printMessage() {

    printf("This function does not return a value.\n");

}

2.   Generic Pointers: To declare a generic pointer (void *), which is an advanced concept.