C基础第32课--数组指针和指针数组分析

学习自狄泰软件学院唐佐林老师C语言课程，文章中图片取自老师的PPT，仅用于个人笔记。

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定义数组类型

通过数组类型定义数组指针，或者直接定义数组指针

实验1 : 数组类型 + 数组指针

#include 

//定义数组类型
typedef int(AINT5)[5];
typedef float(AFLOAT10)[10];
typedef char(ACHAR9)[9];

int main()
{
    AINT5 a1; //定义数组 int a1[5]
    float fArray[10];
    
    //数组指针 通过数组类型定义数组指针并初始化 指向的目标数组是 类型为float 个数为10的 数组
    AFLOAT10* pf = &fArray;
    ACHAR9 cArray；//定义数组

	//直接定义数组指针
    char(*pc)[9] = &cArray;
	
	// pcw是数组指针，而用来初始化数组指针的是数组首元素的地址，虽然数值和数组地址一样，但是
    char(*pcw)[4] = cArray;  // error
    
    int i = 0;
    
    printf("%d, %d\n", sizeof(AINT5), sizeof(a1));// 20 ,20
    
    for(i=0; i<10; i++)
    {
    	// fArray[i]
        (*pf)[i] = i;
    }
    
    for(i=0; i<10; i++)
    {
        printf("%f\n", fArray[i]);
    }
    
    // 打印地址值
    // pc+1 == (unsigned int)pc + sizeof(*pc)==pc+9
    // pcw+1 == (unsigned int)pcw+ sizeof(*pcw)==pc+4
    printf("%p, %p, %p\n", &cArray, pc+1, pcw+1);

    return 0;
}


mhr@ubuntu:~/work/C$ 
mhr@ubuntu:~/work/C$ 
mhr@ubuntu:~/work/C$ gcc 32-1.c
32-1.c: In function ‘main’:
32-1.c:15:21: warning: initialization from incompatible pointer type [-Wincompatible-pointer-types]
     char(*pcw)[4] = cArray;
                     ^
32-1.c:19:12: warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘long unsigned int’ [-Wformat=]
     printf("%d, %d\n", sizeof(AINT5), sizeof(a1));
            ^
32-1.c:19:12: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘long unsigned int’ [-Wformat=]
mhr@ubuntu:~/work/C$ 
mhr@ubuntu:~/work/C$ 
mhr@ubuntu:~/work/C$ 
mhr@ubuntu:~/work/C$ ./a.out 
20, 20
0.000000
1.000000
2.000000
3.000000
4.000000
5.000000
6.000000
7.000000
8.000000
9.000000
0x7fff72faeec0, 0x7fff72faeec9, 0x7fff72faeec4
mhr@ubuntu:~/work/C$ 

实验2：指针数组

#include 
#include 

//求数组大小
#define DIM(a) (sizeof(a)/sizeof(*a))

// 在 const char* table[] 指针数组中遍历 搜索const char* key指向的字符串 并返回下标
int lookup_keyword(const char* key, const char* table[], const int size)
{
    int ret = -1;
    
    int i = 0;
    
    for(i=0; i