C++ 数据类型

基本的内置类型

实例

#include<iostream>  
#include<string>  
#include <limits>  
using namespace std;  
  
int main()  
{  
    cout << "type: \t\t" << "************size**************"<< endl;  
    cout << "bool: \t\t" << "所占字节数：" << sizeof(bool);  
    cout << "\t最大值：" << (numeric_limits<bool>::max)();  
    cout << "\t\t最小值：" << (numeric_limits<bool>::min)() << endl;  
    cout << "char: \t\t" << "所占字节数：" << sizeof(char);  
    cout << "\t最大值：" << (numeric_limits<char>::max)();  
    cout << "\t\t最小值：" << (numeric_limits<char>::min)() << endl;  
    cout << "signed char: \t" << "所占字节数：" << sizeof(signed char);  
    cout << "\t最大值：" << (numeric_limits<signed char>::max)();  
    cout << "\t\t最小值：" << (numeric_limits<signed char>::min)() << endl;  
    cout << "unsigned char: \t" << "所占字节数：" << sizeof(unsigned char);  
    cout << "\t最大值：" << (numeric_limits<unsigned char>::max)();  
    cout << "\t\t最小值：" << (numeric_limits<unsigned char>::min)() << endl;  
    cout << "wchar_t: \t" << "所占字节数：" << sizeof(wchar_t);  
    cout << "\t最大值：" << (numeric_limits<wchar_t>::max)();  
    cout << "\t\t最小值：" << (numeric_limits<wchar_t>::min)() << endl;  
    cout << "short: \t\t" << "所占字节数：" << sizeof(short);  
    cout << "\t最大值：" << (numeric_limits<short>::max)();  
    cout << "\t\t最小值：" << (numeric_limits<short>::min)() << endl;  
    cout << "int: \t\t" << "所占字节数：" << sizeof(int);  
    cout << "\t最大值：" << (numeric_limits<int>::max)();  
    cout << "\t最小值：" << (numeric_limits<int>::min)() << endl;  
    cout << "unsigned: \t" << "所占字节数：" << sizeof(unsigned);  
    cout << "\t最大值：" << (numeric_limits<unsigned>::max)();  
    cout << "\t最小值：" << (numeric_limits<unsigned>::min)() << endl;  
    cout << "long: \t\t" << "所占字节数：" << sizeof(long);  
    cout << "\t最大值：" << (numeric_limits<long>::max)();  
    cout << "\t最小值：" << (numeric_limits<long>::min)() << endl;  
    cout << "unsigned long: \t" << "所占字节数：" << sizeof(unsigned long);  
    cout << "\t最大值：" << (numeric_limits<unsigned long>::max)();  
    cout << "\t最小值：" << (numeric_limits<unsigned long>::min)() << endl;  
    cout << "double: \t" << "所占字节数：" << sizeof(double);  
    cout << "\t最大值：" << (numeric_limits<double>::max)();  
    cout << "\t最小值：" << (numeric_limits<double>::min)() << endl;  
    cout << "long double: \t" << "所占字节数：" << sizeof(long double);  
    cout << "\t最大值：" << (numeric_limits<long double>::max)();  
    cout << "\t最小值：" << (numeric_limits<long double>::min)() << endl;  
    cout << "float: \t\t" << "所占字节数：" << sizeof(float);  
    cout << "\t最大值：" << (numeric_limits<float>::max)();  
    cout << "\t最小值：" << (numeric_limits<float>::min)() << endl;  
    cout << "size_t: \t" << "所占字节数：" << sizeof(size_t);  
    cout << "\t最大值：" << (numeric_limits<size_t>::max)();  
    cout << "\t最小值：" << (numeric_limits<size_t>::min)() << endl;  
    cout << "string: \t" << "所占字节数：" << sizeof(string) << endl;  
    // << "\t最大值：" << (numeric_limits<string>::max)() << "\t最小值：" << (numeric_limits<string>::min)() << endl;  
    cout << "type: \t\t" << "************size**************"<< endl;  
    return 0;  
}

枚举类型

enum 枚举名{ 
     标识符[=整型常数], 
     标识符[=整型常数], 
... 
    标识符[=整型常数]
} 枚举变量;

例如，下面的代码定义了一个颜色枚举，变量 c 的类型为 color。最后，c 被赋值为 "blue"。

enum color { red, green, blue } c;
c = blue;

默认情况下，第一个名称的值为 0，第二个名称的值为 1，第三个名称的值为 2，以此类推。但是，您也可以给名称赋予一个特殊的值，只需要添加一个初始值即可。例如，在下面的枚举中，green 的值为 5。

enum color { red, green=5, blue };

在这里，blue 的值为 6，因为默认情况下，每个名称都会比它前面一个名称大 1，但 red 的值依然为 0。