[C++知识库]c++基本数据类型的大小及范围

1?数据大小

注意，c语言中没有bool类型，用0代表false，用非0代表true

测试平台：VS2015的debug模式下X86

#include <iostream>
using namespace std;

int main(int argc, char* argv[]) {
	cout << "sizeof(bool) = " << sizeof(bool) << endl;
	cout << "sizeof(char) = " << sizeof(char) << endl;
	cout << "sizeof(unsigned char) = " << sizeof(unsigned char) << endl;
	cout << "sizeof(short int) = " << sizeof(short int) << endl;
	cout << "sizeof(int) = " << sizeof(int) << endl;
	cout << "sizeof(unsigned int) = " << sizeof(unsigned int) << endl;
	cout << "sizeof(float) = " << sizeof(float) << endl;
	cout << "sizeof(long) = " << sizeof(long) << endl;
	cout << "sizeof(unsigned long) = " << sizeof(unsigned long) << endl;
	cout << "sizeof(double) = " << sizeof(double) << endl;
	cout << "sizeof(long long) = " << sizeof(long long) << endl;

	cout << "指针" << endl;

	cout << "sizeof(bool*) = " << sizeof(bool*) << endl;
	cout << "sizeof(char*) = " << sizeof(char*) << endl;
	cout << "sizeof(unsigned char*) = " << sizeof(unsigned char*) << endl;
	cout << "sizeof(short int*) = " << sizeof(short int*) << endl;
	cout << "sizeof(int*) = " << sizeof(int*) << endl;
	cout << "sizeof(unsigned int*) = " << sizeof(unsigned int*) << endl;
	cout << "sizeof(float*) = " << sizeof(float*) << endl;
	cout << "sizeof(long*) = " << sizeof(long*) << endl;
	cout << "sizeof(unsigned long*) = " << sizeof(unsigned long*) << endl;
	cout << "sizeof(double*) = " << sizeof(double*) << endl;
	cout << "sizeof(long long*) = " << sizeof(long*) << endl;

	system("pause");
	return 0;
}

运行如下：

总结如下：

测试平台：VS2015的debug模式下X64

代码同上

总结

这里有个怪异的地方?，我们平常说long是8个字节，这里却是4个字节。

我决定试试linux平台，看看结果。

先看32位

在g++后面添加-m32

g++ -m32 -自己的代码

需要安装一些库

sudo apt-get install build-essential module-assistant  
sudo apt-get install gcc-multilib g++-multilib  

结果

?与windows下32位一样

再测64位

?发现这里long和unsigned?long都是8个字节，其他没有变化。

?总结

windows系统和linux系统下，大部分数据类型的大小都一样，只有long和unsigned?long不一样；

在window下64位机器上，long和unsigned?long都是4个字节

在linux下64位机器人上，long和unsigned?long都是8个字节

2?范围

参考：

1、ubuntu G++编译32位_houxy12的博客-CSDN博客_g++ 编译32位

2、(1条消息) c语言基本数据类型大小（32位/64位操作系统）_华科????的博客-CSDN博客_c语言变量类型64位

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