C-pointer-lab/pointer.c at main · HasibCoderLab/C-pointer-lab · GitHub

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// ================================================
//               * Language: C
//               * Topic: Pointer
// =================================================

// pointer example  1️⃣
#include <stdio.h>
int main(){
     int age = 20 ;
     int *ptr  = &age;
     int _age = *ptr ;
     printf(" Output is %d\n" , _age);
    return 0;
}

//    Print Address

#include <stdio.h>
int main()
{
    int age = 10;
    int *ptr = &age;
    int _age = *ptr;
  //printf("Output is %p\n" ,&age );
    printf("Output is %u\n", &ptr); //  Different
    printf("Output is %u\n", ptr);
    printf("Output is %u\n", &age);

    return 0;
}

//  Print value
#include <stdio.h>
int main(){
int age = 12 ;
int *ptr = &age ;
int _age = *ptr;
printf("Output is : %d\n", age);
printf("Output is : %d\n" , *ptr);
printf("Output is : %d\n" , *(&age)) ;
return 0;
}

// ================================================
//               * Language: C
//               * Topic: Pointer  to Pointer
// =================================================

// pointer example  2️⃣

#include <stdio.h>
int main()
{
    int price = 100;
    int *ptr = &price;
    int **pptr = &ptr;
    return 0;
}

//  3️⃣   Call by value

#include <stdio.h>
void num(int n);
int main(){
int number = 10;
num(number);
printf("Number is %d\n" , number );
return 0;
}

void num(int n){
    n = n*n;
    printf("Square  is %d\n " , n);
}

//  4️⃣   Call by Reference

#include <stdio.h>
void _square(int *n);
void square(int a);

int main()
{
    int x = 4;
    // int y = 3;
    square(x); // function call
    printf("value of x %d\n", x);
    _square(&x);
    printf("value of &x %d\n", x);
    return 0;
}
// fuction definition
void square(int a)
{
    // a = a*a;
    int result = a * a;
    printf(" Result of square  %d\n", result);
}
void _square(int *n)
{
    *n = (*n) * (*n);
    printf("_square is %d\n", *n);
}

// 👉👉  🔹🔹Qexample -   5️⃣ Swap 2 Numbers  a & b

#include <stdio.h>
int main(){
  int a = 55 ;
  int b = 33;

  int  t = a;
  a = b ;
  b = t;
  printf("a = %d  & b = %d\n" , a  ,b);
    return 0;
}

// 👉👉  🔹🔹example -   6️⃣ Swap 2 Numbers  a & b call by reference

#include <stdio.h>
int _swap(int *a ,int *b);
int main(){
    int a = 10;
    int b = 20;
    _swap(&a ,&b);
    printf("a =  %d b = %d\n" ,a,b );
    return 0 ;

}
// Fucntion difinition;
int _swap(int *a , int *b){
    int t= *a;
    *a = *b;
    *b = t;
printf("a = %d & b = %d\n", *a,*b);
}