C++学习（一）——基本程序设计

1、首先练习鸡兔同笼问题：

 1 #include <iostream>
 2 using namespace std;
 3 int main()
 4 {
 5     int a,b,x,y;
 6     cout << "请输入鸡和兔的总数：";
 7     cin >> a;
 8     cout << "请输入鸡和兔的总脚数：";
 9     cin >> b;
10     x = (4 * a - b) / 2;
11     y = (b - 2 * a) / 2;
12     cout << "鸡的总数为：" << x << endl;
13     cout << "鸭的总数为：" << y << endl;
14     return 0;
15 }

说实话，cnbolog的代码字体看起来不是很满意。

2、输出成绩求平均值问题

 1 #include <iostream>
 2 #include <iomanip>
 3 using namespace std;
 4 int main()
 5 {
 6 // 输入考试成绩求平均值问题
 7     // include<iomanip>
 8     float score1,score2,score3,average;
 9     cout << "请输入三门课程的考试成绩：" << endl;
10     cin >> score1 >> score2 >> score3;
11     average = (score1 + score2 + score3) / 3;
12     cout << setw(10) << "科目" << setw(12) << "成绩" << endl;
13     cout << setw(10) << "英语" << setw(12) << score1 << endl;
14     cout << setw(10) << "程序设计" << setw(12) << score2 << endl;
15     cout << setw(10) << "大学物理" << setw(12) << score3 << endl;
16     cout << fixed;
17     cout.precision(2);
18     cout << "该生的平均成绩为：" << average << endl;
19     return 0;
20 }

3、leap year or not

 1     int year;
 2     cout << "Enter the year:" << endl;
 3     cin >> year;
 4     if (year%4==0 && year%100!=0 || year%400==0)
 5     {
 6         cout << year << " is a leap year. " << endl;
 7     }
 8     else
 9     {
10         cout << year << " is not a leap year. " << endl;
11     }
12     return 0;