How to Simplify Complex Type Declarations in C with typedef

In C, the typedef keyword is used to define an alternative name  for an existing data type.

which can simplify code readability and make it easier to change data types in one place if needed.

By using typedef, you can define a new name for an existing data type, which is particularly helpful for complex or lengthy type declarations.

Syntax

 typedef existing_type new_type

 Typedef  on integers:

#include

Typedef unsigned int  uint

 Int main()

{

Uint  age=10;

Uint salary=2500;

Printf(“%d”,salary);

Printf(“%d”,age”);

}

Similar way works for float (Typedef float * floatpoint) and double

Typedef with Pointers

typedef is useful for creating aliases for complex pointer types, making code involving function pointers or struct pointers easier to read.

#include

typedef int* Intptr;

typedef unsigned int  uint;

 int main()

{

uint  age=10;

Intptr ptr=&age;

printf(“%d\n”,*ptr);

uint salary=2500;

printf(“%d\n”,salary);

printf(“%d\n”,age);

}

Examples of typedef in C

1. typedef with struct

Without typedef:

struct Student {    

char name[50];    

int age;}; 

struct Stu s1, s2; // We have to use `struct Student` each time

With typedef:

typedef struct {
char name[50];
int age;
} Stu;

Stu s1, s2;

Example Program
#include<stdio.h>
typedef int* Intptr;
typedef unsigned int uint;
typedef struct node
{
int data;
char a[10];
}Node;

int main()
{
Node* n= (Node*)malloc(sizeof(Node));
printf(“Enter the data”);
scanf(“%d”,&n->data);
printf(“Enter the character array”);
scanf(“%s”, n->a);

uint age=10;
Intptr ptr=&age;
printf(“%d\n”,*ptr);
uint salary=2500;
printf(“%d\n”,salary);
printf(“%d\n”,age);
printf(“%d\n”,n->data);
printf(“%s\n”,n->a);
}

Function Pointer Example:

 typedef int (*Operation)(int, int); // Function pointer type alias

int calculateadd(int a, int b) { return a + b; }

Operation op = add;

Here, Operation is an alias for a function pointer that points to functions taking two int arguments and returning an int.

#include

#define x 10;

#define y 5;

// Define a function pointer type alias for operations on two integers

typedef int (*Operation)(int, int);

// Define functions for different operations

void performOperation(Operation op, int x, int y, const char* opName) {

    printf(“Result of %s: %d\n”, opName, op(x, y));

}

int main() {

    // Use the Operation function pointer alias to perform different operations

    performOperation(calculateadd1, x, y, “Addition”);

    performOperation(calculatesub1, x, y, “Subtraction”);

    performOperation(calculatemul1, x, y, “Multiplication”);

    performOperation(calculatediv1, x, y, “Division”);

    return 0;

}

3. typedef with Arrays

You can use typedef to create type aliases for arrays, which can simplify code dealing with fixed-size arrays.

 typedef int Array10[10]; // Array of 10 integersArray10 numbers;         // `numbers` is now an array of 10 integers

This alias makes it clear what numbers represents, particularly when you need multiple arrays of the same size.

Example program

#include

typedef int* Intptr;

typedef unsigned int  uint;

typedef  int array10[5];

typedef struct node

{

    int data;

    char a[10];

}Node;

 int main()

{

        array10  numbers;

        for(int y=0;y<5;y++)

    {

        printf(“Enter %d elements”,y+1);

      scanf(“%d”,&numbers[y])  ;

    }

    Node* n=  (Node*)malloc(sizeof(Node));

    printf(“Enter the data”);

    scanf(“%d”,&n->data);

    printf(“Enter the character array”);

    scanf(“%s”, n->a);

uint  age=10;

Intptr ptr=&age;

printf(“%d\n”,*ptr);

uint salary=2500;

printf(“%d\n”,salary);

printf(“%d\n”,age);

printf(“%d\n”,n->data);

printf(“%s\n”,n->a);

}

typedef vs #define in C

typedef and #define can both create type aliases, but they are used differently and have distinct purposes.