项目练习1.2

#include <iostream>
#include <string>
#include <Windows.h>
using namespace std;
int main(void) {
      char c;
      cout << "请输入一个字符: " << endl;
      cin >> c;
      if (c >= 'a' && c <='z') {
            c = c - 'a' + 'A';
      } else if (c >= 'A' && c <= 'Z') {
            c = c - 'A' + 'a';
      }
      cout << c << endl;
      system("pause");
      return 0;
}

#include <iostream>
#include <string>
#include <Windows.h>
using namespace std;
//零 壹 贰 叁 肆 伍 陆  柒 捌 玖
int main(void) {
      int num;
      string ret;
      cout << "请输入一个数字[0-9]: ";
      cin >> num;
      switch (num) {
      case 0:
            cout << "零";
            break;
      case 1:
            cout << "壹";
            break;
      case 2:
            cout << "贰";
            break;
      case 3:
            cout << "叁";
            break;
      case 4:
            cout << "肆";
            break;
      case 5:
            cout << "伍";
            break;
      case 6:
            cout << "陆";
            break;
      case 7:
            cout << "柒";
            break;
      case 8:
            cout << "捌";
            break;
      case 9:
            cout << "玖";
            break;
      default:
            break;
      }
      cout << endl;
      system("pause");
      return 0;
}

#include <iostream>
#include <string>
#include <Windows.h>
using namespace std;
int main(void) {
      int num;
      string ret[10] = {"零", "壹", "贰", "叁", "肆", "伍",  "陆",  "柒",  "捌",  "玖"};
      cout << "请输入一个数字[0-9]: ";
      cin >> num;
      if (num >=0 && num <=9) {
            cout << ret[num] << endl;
      }
      system("pause");
      return 0;
}

#include <iostream>
#include <Windows.h>
#include <string>
using namespace std;
/*
闰年的2月份有29天
普通闰年: 能被4整除但不能被100整除的年份为
世纪闰年: 能被400整除
*/
int main(void) {
         int year;
         int month;
         bool flag = false;
         int days;
         cout << "请输入年份：";
         cin >> year;
         cout << "请输入月份：";
         cin >> month;
         if (year % 400 == 0) {
                  flag = true;
         } else if (year % 4 == 0  &&  year % 100 != 0) {
                  flag = true;
         } else {
                  flag = false;
         }
         switch (month) {
         case 1:
         case 3:
         case 5:
         case 7:
         case 8:
         case 10:
         case 12:
                  days = 31;
                  break;
         case 2:
                  days = flag ? 29 : 28;
                  break;
         case 4:
         case 6:
         case 9:
         case 11:
                  days = 30;
                  break;
         default:
                  std::cout << "无效月份" << std::endl;
                  break;
         }
         cout <<  year << "年" << month << "月一共有：" << days << "天" << endl;
         system("pause");
         return 0;
}