//短整型(-32768~32767)

short num1 = 32769;//输出就是一个负数-32768

//整型

int num2 = 10;

//长整型

long num3 = 10;

//长长整型

long long num4 = 10;

cout << "num1= " << num1 << endl;

cout << "num2= " << num2 << endl;

cout << "num3= " << num3 << endl;

cout << "num4= " << num4 << endl;

b = sizeof(a);

float f1 = 3.14f;//不加f会默认double类型的，会多一步转化

cout << f1 << endl;

double d1 = 3.14;

cout << d1 << endl;

//统计float和double所占内存空间

cout <<"float占用的内存空间："<< sizeof(float) << endl;

cout << "double占用的内存空间：" << sizeof(double) << endl;

//科学计数法

float f2 = 3e2;//3*10^2;

cout << "f2=" << f2 << endl;

float f3 = 3e-2;//3*0.1^2;

cout << "f3=" << f3 << endl;

//1、字符型变量创建方式

char ch = 'a';

cout << ch << endl;

//2、字符型变量所占内存空间大小

cout << "char字符型所占内存：" << sizeof(ch) << endl;

//3、字符型变量对应的ASCII编码

cout << (int)ch << endl;

//C风格

char str[] = "hello world";

cout << str << endl;

//C++风格

string ss = "hello C++";  //需要一个#include头文件

cout << ss << endl;

//1、创建bool类型

bool flag = true;

bool flag1 = false;

cout << flag << endl;

cout << flag1 << endl;

//2、查看内存空间

cout << "bool类型所占的内存空间：" << sizeof(flag) << endl;

cout << "请输入a的值：" << endl;

cin >> a;