宏定义（数组名不是一个作为变量的指针）

  在C++中练习了下宏的定义，有个关于delete的宏，释放指针，指针数组，结构体等，期间出现了一个错误，我定义了一个数组int p0[2] = {2, 3};然后调用宏函数释放数组，但是是不行的，数组名本身不能作为指针或者变量，它是一个地址常量，因此宏函数#define SAFE_DELETE_ARRAY(p) {if (p) {delete[] (p); (p) = NULL;}}中if (p)的调用显然就出错了；而普通函数调用时，数组名作为参数传入时，数组名会自动退化为指针，这点对于宏来说做不到，本身宏就是一个替换作为，所以再学习....

/*
 * macro_cpp.cpp
 *
 *  Created on: 2012-7-19
 *      Author: Administrator
 */

#include <iostream>
#include <stdlib.h>
#include <typeinfo>
using namespace std;

#define SAFE_DELETE(p)       { if(p) { delete (p);     (p)=NULL; } }
#define SAFE_DELETE_ARRAY(p) { if(p) { delete[] (p);   (p)=NULL; } }
#define SAFE_RELEASE(p)      { if(p) { (p)->Release(); (p)=NULL; } }

int *array = NULL;
#define RAND_ARRAY2(n) do{        \
        array = (int *)malloc(sizeof(int) * n);        \
        for (int i = 0; i < n; i++){       \
            array[i] = i; \
        } \
}while(0);

int main() {
    int *sb = (int *) 2;
    SAFE_DELETE(sb);
    int p0[2] = {2, 4};
    int* p1 = new int[2];
    int (*p2)[4] = new int[2][4];
    cout << p0[0] << endl;
    //SAFE_DELETE_ARRAY(p0);//wrong 数组名是一个地址，一个符号地址常量，不是一个变量，更不是一个作为变量的指针！
    SAFE_DELETE_ARRAY(p1);
    SAFE_DELETE_ARRAY(p2);

    int a[3] = { 1, 2, 3 };
    cout << sizeof a / sizeof(typeid( a[0] ).name()) << endl; //typeid().name() return data_type

    RAND_ARRAY2(4);
    cout << "....." << array[0] <<"....." << array[1] << endl;

    return 0;
}

/*
 ============================================================================
 Name        : macro.c
 Author      : hl
 Version     :
 Copyright   : Your copyright notice
 Description : Macro in C, Ansi-style
 ============================================================================
 */

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

#define MAX(a, b) ((a > b) ? (a) : (b))
#define IS_EVEN(n) ((n)%2 == 0)
#define RAND_ARRAY(array, n) do{        \
        array = (int *)malloc(sizeof(int) * n);        \
        int i;    \
        for (i = 0; i < n; i++){       \
            array[i] = i; \
        } \
}while(0);

int main(void) {
    printf("max(%d, %d) return max_number is %d\n", 7, 6, MAX(7, 6));
    printf("number %d %s even\n", 4, IS_EVEN(4) ? ("is") : ("is not"));
    //预定义宏
    fprintf(stdout, "Line %d at %s, time is %s %s, %s standerd c\n", __LINE__, __FILE__, __DATE__, __TIME__, __STDC__ ? "is" : "is not");
    //函数宏
    int *array = NULL;
    RAND_ARRAY(array, 4);
    printf("array[%d] is %d\n", 3, array[3]);

    return EXIT_SUCCESS;
}