#include <iostream>
#include <string>
using namespace std;
//单行 注释
/*多行注释*/
//常量定义
#define Month 12;
#define Day 31;
/*main为c++的入口函数*/
int main()
{
//变量定义
char b = 'B';
int a = 10;
const int hours = 24;
const bool flags = true;
cout << "hello world " << endl;
cout << "a = " << a << endl;
cout << "b = " << b << endl;
cout << "\n";
cout << "\n";
cout << "\n";
cout << "\n";
cout << "\n";
cout << "\n";
float second = 60.0009f; // 单精度浮点
cout << "年份 ="<< Day;
cout << "月份 =" << Month;
cout << "小时 =" << hours;
cout << "\n";
cout << "one minute has " <<second << " s";
cout << "\n";
cout << "\b";
cout << "\b";
int Times = hours * Month;
cout << "Month * Hours ==" << Times;
cout << "\n";
cout << "\n";
cout << "\n";
cout << "\n";
cout << "\n";
//sizeof关键字:统计字节数
cout << "short占空间:" << sizeof(short);
cout << "int占空间:" << sizeof(int);
cout << "long占空间:" << sizeof(long);
cout << "long long 占空间:" << sizeof(long long);
cout << "Month 占空间：" << sizeof Month;
cout << "second占空间：" << sizeof second;
cout << "char 占空间:" << sizeof(char);
cout << "\n";
cout << "\n";
cout << "\n";
//字符型
char ch = 'a'; //只能有一个变量,单引号
cout << ch << endl;
cout << sizeof ch << endl;
cout << int(ch) << endl; //字符串转换为ASCII码值
//字符串型
char s1[] = "this is that ";//C >字符数组，双引号
string s2 = "this is not";//C++ >字符数组，双引号。头文件标识#include <string>
cout << s1 << endl;
cout << s2 << endl;
//布尔类型
bool flag = true;
bool unflag = false;
cout << flag << endl; //0
cout << unflag << endl; //1
cout << sizeof flag << endl;
/*
//cin 数据输入：从键盘获取输入
int mya = 0;
cout <<"How old are u ? " << endl;
cin >> mya;
cout << "U are " << mya<<" years old "<<endl;
string talk = "";
cout << "What did u say?" << endl;
cin >> talk;
cout << "U said :" << talk << endl;
cout << "\n" << endl;
cout << "\n" << endl;
cout << "\n" << endl;
*/
//运算符
int a1 = 10;
int a2 = 20;
int a1_a2 = a1 + a2;
cout << a1_a2 << endl;
//递增运算符
int a1 = 30;
a1++;
cout << a << endl;
system("pause");
return 0;
