C Data Types

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In C programming, data types define the nature of the data that can be stored in variables. They determine the size of the data and the operations that can be performed on it. C provides several data types that are categorized into basic, derived, enumeration, and void types.

Categories of Data Types in C

Types Data Types
Basic Data Type int, char, float, double
Derived Data Type array, pointer, structure, union
Enumeration Data Type enum
Void Data Type void

1. Basic Data Types

Basic data types are the fundamental data types in C, and they are further classified into integer and floating-point types. The size of these data types can vary based on the system architecture (e.g., 32-bit or 64-bit).

Basic Data Types and Their Sizes (for 32-bit Architecture):

Data Type Memory Size Range
char 1 byte −128 to 127
signed char 1 byte −128 to 127
unsigned char 1 byte 0 to 255
short 2 bytes −32,768 to 32,767
signed short 2 bytes −32,768 to 32,767
unsigned short 2 bytes 0 to 65,535
int 2 bytes −32,768 to 32,767
signed int 2 bytes −32,768 to 32,767
unsigned int 2 bytes 0 to 65,535
short int 2 bytes −32,768 to 32,767
signed short int 2 bytes −32,768 to 32,767
unsigned short int 2 bytes 0 to 65,535
long int 4 bytes -2,147,483,648 to 2,147,483,647
signed long int 4 bytes -2,147,483,648 to 2,147,483,647
unsigned long int 4 bytes 0 to 4,294,967,295
float 4 bytes Approx. ±3.4 × 1038, 6 decimal places
double 8 bytes Approx. ±1.7 × 10308, 15 decimal places
long double 10 bytes Larger range and precision than double

Example:

<#include <stdio.h>>

int main() {
    int age = 25;
    char grade = 'A';
    float temperature = 98.6;
    double pi = 3.14159265359;

    printf("Age: %d\\n", age);
    printf("Grade: %c\\n", grade);
    printf("Temperature: %.1f\\n", temperature);
    printf("Pi: %.11f\\n", pi);

    return 0;
}

Output:

Age: 25
Grade: A
Temperature: 98.6
Pi: 3.14159265359

2. Derived Data Types

Derived data types are built from the basic data types and include arrays, pointers, structures, and unions.

Array:

An array is a collection of elements of the same type stored in contiguous memory locations.

Example:

<#include <stdio.h>>

int main() {
    int numbers[5] = {10, 20, 30, 40, 50};

    printf("Values in the array: ");
    for (int i = 0; i < 5; i++) {
        printf("%d ", numbers[i]);
    }
    printf("\\n");

    return 0;
}

Output:

Values in the array: 10 20 30 40 50

Pointer:

A pointer holds the memory address of another variable. It is used for dynamic memory allocation, function arguments, and arrays.

Example:

<#include <stdio.h>>

int main() {
    int num = 42;
    int *ptr = &num;

    printf("Value of num: %d\\n", *ptr);

    return 0;
}

Output:

Value of num: 42

Structure:

A structure allows the grouping of variables of different types under a single name. Structures are useful for representing complex data.

Example:

<#include <stdio.h>>
<#include <string.h>>

struct Person {
    char name[50];
    int age;
    float height;
};

int main() {
    struct Person person1;
    strcpy(person1.name, "John Doe");
    person1.age = 30;
    person1.height = 1.8;

    printf("Name: %s\\n", person1.name);
    printf("Age: %d\\n", person1.age);
    printf("Height: %.2f\\n", person1.height);

    return 0;
}

Output:

Name: John Doe
Age: 30
Height: 1.80

Union:

A union allows storing different data types in the same memory location. All members share the same memory, so only one member can hold a value at a time.

Example:


<#include <stdio.h>>

union NumericValue {
    int intValue;
    float floatValue;
    char stringValue[20];
};

int main() {
    union NumericValue value;
    value.intValue = 42;

    printf("Integer Value: %d\\n", value.intValue);

    value.floatValue = 3.14;
    printf("Float Value: %.2f\\n", value.floatValue);

    return 0;
}

Output:

Integer Value: 42 Float Value: 3.14

3. Enumeration Data Types

An enumeration defines a set of named integer constants. It improves code readability and maintainability.

Example:

<#include <stdio.h>>

enum DaysOfWeek {
    Monday,
    Tuesday,
    Wednesday,
    Thursday,
    Friday,
    Saturday,
    Sunday
};

int main() {
    enum DaysOfWeek today = Wednesday;

    printf("Today is %d\\n", today);

    return 0;
}

4. Void Data Type

The void data type indicates the absence of data or type. It is commonly used for functions that do not return a value and for generic pointers.

Function Return Type Example:

<#include <stdio.h>>

void printHello() {
    printf("way to code\\n");
}

int main() {
    printHello();

    return 0;
}


<#include <stdio.h>>

void printHello() {
    printf("way to code\\n");
}

int main() {
    printHello();

    return 0;
}

Void Pointer Example:

<#include <stdio.h>>

int main() {
    int number = 10;
    void* dataPtr = &number;

    printf("Value of number: %d\\n", *(int*)dataPtr);

    return 0;
}

Conclusion

Data types in C are crucial for defining the nature of data that variables can hold. They affect memory allocation, data manipulation, and overall program performance. Basic data types include integer and floating-point types, while derived data types allow complex data management through arrays, pointers, structures, and unions. Enumeration provides named constants for better readability, and the void type is used for functions that do not return values and generic pointers. Understanding these data types helps in writing efficient and well-structured C programs.

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