指针详解（二级指针、指针数组和数组指针、字符指针、二维数组传递参数、函数指针变量）（II）

int main()
{
	int a = 10;
	int *p = &a;//取出a的地址
	//p是指针变量,一级指针
	int*        *      pp = &p;
	//int*说明pp指向的对象的类型是int*
	// *说明pp是变量,pp是二级指针,用来存放以及指针变量的地址
	//指针变量也是变量

	int*** ppp = &pp;//ppp是三级指针(用的很少)
	//...

	printf("%d\n", **pp);


	return 0;
}

int main()
{
	int arr1[] = {1,2,3,4,5};
	int arr2[] = {2,3,4,5,6};
	int arr3[] = {3,4,5,6,7};
	int* arr[3] = { arr1,arr2,arr3 };//整型指针数组,模拟二维数组,但每一行,并不是连续的
	int i = 0;
	for (i = 0; i < 3; i++)
	{
		for (int j = 0; j < i; j++)
		{
			printf("%d ", arr[i][j]);
			//arr[i][j] ==> *(*(arr+i)+j)
		}
		printf("\n");
	}

	return 0;
}

int main()
{
	int arr[10] = { 1,2,3,4,5,6,7,8,9,10 };
	int* p1 = arr;
//  int*      int*
	int* p2 = &arr[0];
//  int*      int*
	int(*p3)[10] = &arr;//p3是数组指针
//	int(*)[10]     int (*)[10]
	//此处[]的优先级高于*
	return 0;
}

int main()
{
	int n = 100;
	int* pn = &n;
	
	char ch = 'w';
	char* pc = &ch;

	float f = 3.14f;
	float* pf = &f;

	int arr[] = { 1,2,3,4,5,6,7,8,9,10 };
	int ** parr = &arr;//取出的是数组的地址,parr是数组指针

	int* p1[10];//p1是数组,数组10个元素,每个元素的类型都是int*,所以p1是指针数组
	int (*p2)[10];//p2是指针,指针指向的是数组,数组有10个元素,每个元素的类型都是int,所以p2是数组指针

	return 0;
}

int main()
{
	int a = 10;
	int* p = &a;
	int* arr[10] = { p };
	int* (*arr[10]);//数组指针，指向的是int*[]指针数组，其中包括指针
	int(*arr)[10];//数组指针，指向的是int[]整型数组
}

int main()
{
	//char ch = 'w';
	//char* pc = &ch;//pc就是字符指针
	
	char* p = "abcdef";//不是把字符串abcdef\0存放在p中
	//而是把首字符的地址放在p中
	//printf("%c\n", *p);
	printf("%c\n", "abcdef"[3]);
	printf("%c\n", p[3]);

	return 0;
}

int main()
{
 const char* pstr = "hello bit.";//这里是把一个字符串放到pstr指针变量里了吗？​
 printf("%s\n", pstr);
 return 0;
}

int main()
{
	char str1[] = "hello bit.";
	char str2[] = "hello bit.";
	const char* str3 = "hello bit.";
	const char* str4 = "hello bit.";
	if (str1 == str2)
		printf("str1 and str2 are same\n");
	else
		printf("str1 and str2 are not same\n");
		//str1 and str2 are not same

	if (str3 == str4)
		printf("str3 and str4 are same\n");
	else
		printf("str3 and str4 are not same\n");
		//str3 and str4 are same

	return 0;
}

void Print(int arr[3][5], int r, int c)
{
	int i = 0;
	for (i = 0; i < r; i++)//控制行
	{
		for (int j = 0; j < c; j++)
		{
			printf("%d ", arr[i][j]);
		}
		printf("\n");
	}
}

int main()
{
	int arr[3][5] = { {1,2,3,4,5},{2,3,4,5,6},{3,4,5,6,7} };
	Print(arr,3,5);//打印arr数组内容
	return 0;
}

void Print(int (*arr)[5], int r, int c)
{
	int i = 0;
	for (i = 0; i < r; i++)//控制行
	{
		for (int j = 0; j < c; j++)
		{
			printf("%d ", *(*(arr+i)+j));
		}
		printf("\n");
	}
}

int main()
{
	int arr[3][5] = { {1,2,3,4,5},{2,3,4,5,6},{3,4,5,6,7} };
	Print(arr, 3, 5);//打印arr数组内容

	return 0;
}

int Add(int x, int y)
{
	return x + y;
}


int main()
{
	int a = 10;
	int* pa = &a;

	int arr[10] = { 0 };
	int (*parr)[10] = &arr;//数组指针
	/*对比:
	数组名是数组首元素的地址
	取地址&数组名是整个数组的地址
	函数名:函数的地址
	取地址&函数名:函数的地址*/
	
	//printf("%p\n", &Add); //00007FF6B57A1348
	//printf("%p\n", Add); //00007FF6B57A1348

	int (*pf)(int,int) = &Add;//pf就是函数指针变量
	//*和pf先结合,*pf为指针,int(*)(int,int)是函数指针类型
	int ret1 = (*pf)(4, 9);//通过解引用的方式调用函数
	//*pf(4,9)是对pf函数的返回值解引用
	printf("%d\n", ret1);//13

	int (*pf2)(int, int) = Add;
	int ret2 = (*pf2)(4, 9);
	printf("%d\n", ret2);//13

	int ret3 = pf2(5, 6);//可以不写*
	printf("%d\n", ret3);//11

	return 0;
}