C++PrimerPlus 第五章 循环和关系表达式（编程练习含答案）

C++PrimerPlus 第五章 循环和关系表达式（编程练习含答案）

//for循环
#include<iostream>
int main()
{
	using namespace std;

	int a, b, sum = 0;

	cout << "计算并输出两个整数之间（包括这两个整数）所有整数的和" << endl;
	cout << "输入较小的整数：";
	cin >> a;
	cout << "输入较大的整数：";
	cin >> b;

	for (int i = a; i <= b; i++) {
		sum += i;
	}
	cout << "从" << a << "到" << b << "之间所有整数的和为：" << sum;

	return 0;
}
//while循环
#include<iostream>
int main()
{
	using namespace std;

	int a, b, sum = 0;

	cout << "计算并输出两个整数之间（包括这两个整数）所有整数的和" << endl;
	cout << "输入较小的整数：";
	cin >> a;
	cout << "输入较大的整数：";
	cin >> b;

	int i = a;
	while (i <= b) 
	{
		sum += i;
		i++;
	}
	cout << "从" << a << "到" << b << "之间所有整数的和为：" << sum;

	return 0;
}

#include<iostream>
#include<Array>
const int ArSize = 101;
int main()
{
	using namespace std;
	array<long double, ArSize>factorials;
	factorials[1] = factorials[0] = 1L;
	for (int i = 2; i < ArSize; i++)
		factorials[i] = i * factorials[i - 1];
	for (int i = 0; i < ArSize; i++)
		cout << i << "! = " << factorials[i] << endl;
	return 0;
}

#include<iostream>
int main()
{
	using namespace std;
	double a;
	double sum = 0;

	cout << "请输入一个数字：";
	cin >> a;
	while (a != 0) {
		sum += a;
		cout << "到目前为止，输入的数字累计和为：" << sum << endl;
		cout << "请输入一个数字：";
		cin >> a;
	}
	return 0;
}

#include<iostream>
int main()
{
	using namespace std;
	const double rate_daphne = 0.1;
	const double rate_cleo = 0.05;
	const double init_daphne = 100;
	const double init_cleo = 100;
	double sum_daphne = init_daphne;
	double sum_cleo = init_cleo;
	int year = 0;

	while (sum_daphne >= sum_cleo)
	{
		year += 1;
		sum_daphne = sum_daphne + init_daphne * rate_daphne;
		sum_cleo = rate_cleo * sum_cleo + sum_cleo;
	}
	cout << "第" << year << "年Cleo的投资价值超过Daphne的投资价值。" << endl;
	cout << "Daphne的投资价值为：" << sum_daphne << endl;
	cout << "Cleo的投资价值为：" << sum_cleo << endl;
	return 0;
}

//char*
#include<iostream>
int main()
{
	using namespace std;
	
	const char* month[12] = { "一月","二月", "三月", "四月", "五月", "六月", "七月", "八月", "九月", "十月", "十一月", "十二月" };
	int num[12];
	int sum = 0;

	for (int i = 0; i < 12; i++)
	{
		cout << "输入" << month[i] << "的销售量：";
		cin >> num[i];
	}
	for (int i = 0; i < 12; i++)
		sum += num[i];
	cout << "全年销售量总和：" << sum << endl;
	return 0;
}
//string
#include<iostream>
#include<string>
int main()
{
	using namespace std;
	
	const string month[12] = { "一月","二月", "三月", "四月", "五月", "六月", "七月", "八月", "九月", "十月", "十一月", "十二月" };
	int num[12];
	int sum = 0;

	for (int i = 0; i < 12; i++)
	{
		cout << "输入" << month[i] << "的销售量：";
		cin >> num[i];
	}
	for (int i = 0; i < 12; i++)
		sum += num[i];
	cout << "全年销售量总和：" << sum << endl;
	return 0;
}

#include<iostream>
int main()
{
	using namespace std;
	
	const char* month[12] = { "一月","二月", "三月", "四月", "五月", "六月", "七月", "八月", "九月", "十月", "十一月", "十二月" };
	int num[3][12];
	int sum_year = 0;
	int sum_all = 0;
	
	for (int i = 0; i < 3; i++)
	{
		cout << "输入第" << i + 1 << "年数据：" << endl;
		for (int j = 0; j < 12; j++)
		{
			cout << "输入" << month[j] << "的销售量：";
			cin >> num[i][j];
		}
	}
	for (int i = 0; i < 3; i++)
	{
		for (int j = 0; j < 12; j++)
		{
			sum_year += num[i][j];
		}
		cout << "第" << i + 1 << "年的销售总和：" << sum_year << endl;
		sum_all += sum_year;
		sum_year = 0;
	}
	cout << "三年销售量总和：" << sum_all << endl;
	return 0;
}

#include<iostream>
int main()
{
	using namespace std;
	struct car {
		char maker[20];
		int year;
	};

	cout << "How many cars do you wish to catalog? ";
	int num;
	cin >> num;
	cin.get();

	car* cars = new car[num];

	for (int i = 0; i < num; i++)
	{
		cout << "Car #" << i + 1 << ":\n";
		cout << "Please enter the make: ";
		cin.get(cars[i].maker, 20).get();
		cout << "Please enter the year made: ";
		cin>>cars[i].year;
		cin.get();
	}

	cout << "Here is your collection: \n";
	for (int i = 0; i < num; i++)
		cout << cars[i].year << " " << cars[i].maker << endl;
	
	return 0;
}

#include<iostream>
#include<cstring>
int main()
{
	using namespace std;
	char word[50];
	int sum = 0;

	cout << "Enter words (to stop, type the word done):\n";
	
	cin >> word;
	while (strcmp(word, "done"))
	{
		sum++;
		cin >> word;
	}
	cout << "You entered a total of " << sum << " words.";
	
	return 0;
}

#include<iostream>
#include<string>
int main()
{
	using namespace std;
	string word;
	int sum = 0;

	cout << "Enter words (to stop, type the word done):\n";
	
	cin >> word;
	while (word == "done")
	{
		sum++;
		cin >> word;
	}
	cout << "You entered a total of " << sum << " words.";
	
	return 0;
}

//for循环
#include<iostream>
int main()
{
	using namespace std;

	cout << "Enter number of rows: ";
	int num;
	cin >> num;

	for (int i = 1; i <= num; i++)
	{
		for (int j = 0; j < num - i; j++)
			cout << ".";
		for (int k = 0; k < i; k++)
			cout << "*";
		cout << endl;
	}
	
	return 0;
}

//while循环
#include<iostream>
int main()
{
	using namespace std;

	cout << "Enter number of rows: ";
	int num;
	cin >> num;

	int i = 1;
	int j = 0;
	int k = 0;

	while(i <= num)
	{
		j = 0;
		while (j < num - i)
		{
			cout << ".";
			j++;
		}
		k = 0;
		while (k < i)
		{
			cout << "*";
			k++;
		}
		cout << endl;
		i++;
	}
	
	return 0;
}