三種之中常用的是*ptr_num(i+1)

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

int main()
{
    int i;
    //陣列名就是首地址，陣列就是塊連續的記憶體空間
    double num[5]={12,34,66,77,88};
    double *ptr_num = num;
    for(i=0;i<5;i++){
        //printf("%.2lf\t",ptr_num[i]);  
        printf("%.2lf\t",*ptr_num++);
        //printf("%.2lf\t",*(ptr_num+i));
    }
    printf("\n");
    ptr_num = num;  //用這個方法訪問空間的時候，記得清空首地址
    for(i=0;i<5;i++){
        printf("%.2lf\t",*ptr_num++);
    }

    return 0;
}