C/C++——基本数据类型的大小并且sizeof(int *) = 8

#include <iostream>
using namespace std;

int main()
{
    cout << "sizeof(bool) = " << sizeof(bool) << endl;
    cout << "sizeof(char) = " << sizeof(char) << endl;
    cout << "sizeof(int) = " << sizeof(int) << endl;
    cout << "sizeof(float) = " << sizeof(float) << endl;
    cout << "sizeof(double) = " << sizeof(double) << endl;
    cout << "sizeof(long double) = " << sizeof(long double) << endl;

    enum e{a, b=3};

    cout << "sizeof(enum) = " << sizeof(e) << endl;
    cout << "sizeof(int *) = " << sizeof(int *) << endl;
    cout << "sizeof(char *) = " << sizeof(char *) << endl;


    return 0;
}

运行结果：

sizeof(bool) = 1
sizeof(char) = 1
sizeof(int) = 4
sizeof(float) = 4
sizeof(double) = 8
sizeof(long double) = 16
sizeof(enum) = 4
sizeof(int *) = 8
sizeof(char *) = 8

解释是：在32位编译器上sizeof(指针)是4字节。在64位编译器上sizeof(指针)是8字节。32位地址最大寻址为4G=2^32，64位最大寻址为128T=2^64。