#include <stdio.h>

int main(){
    int a=10;
    int *ptr;
    ptr = &a;
    printf("value of ptr:%d\n",a);
    *ptr=20;
    printf("new value of a:%d\n",a);
    int arr[3]={10,20,30};
    int *p;
    p=arr;
    for(int i=0;i<3;i++){
        printf("arithmetic :%d\n",i,*(p+1));
    }
    printf("value of arr[0]:%d\n",*p);
    p++;
    printf("value of arr[1]:%d\n",*p);
    p++;
    printf("value of arr[2]:%d\n",*p);
    p++;
}