【c++ | 谭浩翔】第四章练习

【p151 第九题】

#include <iostream>
using namespace std;

int main()
{
	int y, d, a, b = 0, i;
	int m[11] = { 31,28,31,30,31,30,31,31,30,31,30 };

	cout << "请输入年份：";
	cin >> y;

	cout << "请输入月份：";
	cin >> a;
	while (a > 12 || a < 1)							//判断月份输入是否正确
	{	
		cout << "请输入正确的月份:";
		cin >> a;
	}

	cout << "请输入日：";						
	cin >> d;
	if (a == 2)									//判断日期输入是否正确
	{
		if (y % 4 == 0 && y % 100 != 0)
		{
			m[2] = m[2] + 1;
			while (d > 29 || d < 1)
			{
				cout << "请输入正确的日期:";		
				cin >> d;
			}
		}
		else
		{
			while (d > 29 || d < 1)
			{
				cout << "请输入正确的日期:";
				cin >> d;
			}
		}
	}
	else
	{
		if (a == 1 || a == 3 || a == 5 || a == 7 || a == 8 || a == 10 || a == 12)
		{
			while (d > 31 || d < 1)
			{
				cout << "请输入正确的日期:";
				cin >> d;
			}
		}
		else
		{
			while (d > 30 || d < 1)
			{
				cout << "请输入正确的日期:";
				cin >> d;
			}
		}
	}
		
	for (i = 0; i < a - 1; i++)							//累计月份的天数
	{
		b += m[i];
	}
	d += b;

	cout << "该日是该年的第" << d << "天";

	return 0;
}

【p151 第十题】

#include <iostream>
#include <string>
using namespace std;

int main()
{
	char f[3][80];

	int a = 0, b = 0, c = 0, d = 0, e = 0;

	for (int i = 0; i < 3; i++)
	{
		cout << "请输入第" << i + 1 <<"行文字:";
		cin >> f[i];

		for (int j = 0; j < 80 && f[i][j] != '\10' ; j++)
		{
			if (f[i][j] >= 'A' && f[i][j] <= 'Z')
				a++;
			else if (f[i][j] >= 'a' && f[i][j] <= 'z')
				b ++;
			else if (f[i][j] >= '0' && f[i][j] <= '9')
				c ++;
			else if (f[i][j] == ' ')
				d ++;
			else e++;
		}
	}

	cout << "共有：" << endl;
	cout << "英文大写字母：" << a << "个" << endl;
	cout << "英文小写字母：" << b << "个" << endl;
	cout << "数字：" << c << "个" << endl;
	cout << "空格：" << d << "个" << endl;
	cout << "其它字符：" << e << "个" << endl;

	return 0;
}
}

【P152 第十四题】

#include <iostream>
#include <string>
using namespace std;

int main()
{
	const int n = 5;
	int i, j;
	string str[n], temp;

	cout << "请输入n个字符串，将按字母由小到大排列输出：" << endl;
	for (i = 0; i < n; i++)
		cin >> str[i];

	for (i = 0; i < n - 1; i++)
	{
		for (j = 0; j < n - i - 1; j++)
		{
			if (str[j] > str[j + 1])
			{
				temp = str[j];
				str[j] = str[j + 1];
				str[j + 1] = temp;
			}
		}
			
	}

	cout << endl << "字母由小到大排列输出:" << endl;
	for (i = 0; i < n; i++)
		cout << str[i] << endl;

	return 0;
}

【p152 第十五题】

#include <iostream>
using namespace std;

int main()
{
	int i;
	const int n = 5;
	char str[n][99];

	cout << "请输入需要判断的字符串" << "（共" << n << "个）：" << endl;
	for (i = 0; i < n; i++)
	{
		cin >> str[i];
	}

	cout << "以下是以字母A打头的字符串：" << endl;
	for (i = 0; i < n; i++)
	{
		if (str[i][0] == 'A')
			cout << str[i] << endl;
	}

	return 0;
}