pointer to structure in c code example

Example 1: how to assign struct address to the pointer

#include<stdio.h>

struct dog
{
    char name[10];
    char breed[10];
    int age;
    char color[10];
};

int main()
{
    struct dog my_dog = {"tyke", "Bulldog", 5, "white"};
    struct dog *ptr_dog;
    ptr_dog = &my_dog;

    printf("Dog's name: %s\n", ptr_dog->name);
    printf("Dog's breed: %s\n", ptr_dog->breed);
    printf("Dog's age: %d\n", ptr_dog->age);
    printf("Dog's color: %s\n", ptr_dog->color);

    // changing the name of dog from tyke to jack
    strcpy(ptr_dog->name, "jack");

    // increasing age of dog by 1 year
    ptr_dog->age++;

    printf("Dog's new name is: %s\n", ptr_dog->name);
    printf("Dog's age is: %d\n", ptr_dog->age);

    // signal to operating system program ran fine
    return 0;
}

Example 2: structs in c

#include <stdio.h>
#include <stdlib.h>

struct book{ //this is like making a datatype of type book
    //these are the fields
  	char name[50];
    char author[50];
    char ISBN[11];
};

int main(){
    struct book book1; //making an instance of book called book1
    /*
    normally to store integers in a struct we can do something like
    book1.number_of_pages = 22; which is correct
    however with character arrays we need to use the strcpy
    function
    */

    strcpy(book1.name, "james and the giant tatti");
    strcpy(book1.author, "Krishan Grewal");
    strcpy(book1.ISBN, "12345678987");

    printf("book name: %s\n", book1.name);
  	printf("book author: %s\n", book1.author);
  	printf("book ISBN: %s\n", book1.ISBN);

return 0;
}

Example 3: how to use a pointer as a parameter in c

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
void add(int* a, int* b, int* c)
{
    *c = *a + *b;
}
int main()
{
	int a, b, c;
	a = 3;
	b = 5;
	add(&a, &b, &c);
	printf("%d", c);
}

Example 4: pointer inside structure in c

#include<stdio.h>

struct Student
{
   int  *ptr;  //Stores address of integer Variable 
   char *name; //Stores address of Character String
}s1;

int main() 
{

int roll = 20;
s1.ptr   = &roll;
s1.name  = "Pritesh";

printf("\nRoll Number of Student : %d",*s1.ptr);
printf("\nName of Student        : %s",s1.name);

return(0);
}