C++ Primer 3.6例题及练习3.43、3.44、3.45

1.例题一：

#include<iostream>
using namespace std;
int main()
{
	constexpr size_t row = 3, col = 4;
	int ia[row][col];
	unsigned cnt = 0;
	for (auto &i : ia)
	{
		for (auto &j : i)
		{
			j = cnt;
			cnt++;
		}
	}
	for (auto &i : ia)
	{
		for (auto j : i)
			cout << j << endl;
	}
	system("pause");
}

2.例题二：

#include<iostream>
#include<iterator>
using namespace std;
int ia[3][4];
int main()
{
	for (auto p = begin(ia); p != end(ia); p++)
	{
		for (auto q = begin(*p); q != end(*p); q++)
		{
			cout << *q << ends;
		}
	}
	system("pause");
}

3.练习3.43：

#include<iostream>
#include<iterator>
using namespace std;
int main()
{
	int ia[3][4] = { 0,1,2,3,4,5,6,7,8,9,10,11 };
	//版本1：范围for语句 
	for (int(&i)[4] : ia)
	{
		for (int j : i)
			cout << j << ends;
	}
	cout << endl;
	//版本2：下标操作
	for (size_t i = 0; i != 3; ++i)
	{
		for (size_t j = 0; j != 4; ++j)
			cout << ia[i][j] << ends;
	}
	cout << endl;
	//版本3：指针操作
	for (int(*i)[4]=ia; i != ia + 3; ++i)
	{
		for (int *j = *i; j != *i + 4; ++j)
			cout << *j << ends;
	}
	cout << endl;
	system("pause");
}

4.练习3.44：

#include<iostream>
using namespace std;
int main()
{
	int ia[3][4]{ 0,1,2,3,4,5,6,7,8,9,10,11 };
	//类型别名
	using int_array = int[4];
	typedef int other;
	for (int_array *p = ia; p != ia + 3; ++p)
	{
		for (other *q = *p; q != *p + 4; q++)
		{
			cout << *q << ends;
		}
	}
	system("pause");
}

5.练习3.45：其实就是例题抄一遍。。

欢迎交流探讨。

谢谢。