// 扩展了 c++ primer中的代码,加了一些自己的注释
#include <iostream>
using namespace std;
int main() {
size_t ia;
ia = sizeof( ia ); // ok
ia = sizeof ia; // ok
// ia = sizeof int; // error
ia = sizeof( int ); // ok
int *pi = new int[ 12 ]; // pi是指针变量,而不是数组名
cout << "pi: " << sizeof( pi )
<< " *pi: " << sizeof( *pi )
<< endl;
// a string's size is independent of
// of the length of the string it addresses
string st1( "foobar" );
string st2( "a might oak" );
string *ps = &st1;
cout << "st1: " << sizeof( st1 )
<< " st2: " << sizeof( st2 )
<< " ps: " << sizeof( ps )
<< " *ps: " << sizeof( *ps )
<< endl;
char *d_str = new char[3];
d_str[0] = 'A';d_str[1] = 'b';d_str[2] = '/0';
cout << "d_str:/t"<< sizeof(d_str) << endl; //4
cout << "*d_str:/t"<< sizeof(*d_str) << endl;//1
cout << "short :/t" << sizeof(short) << endl; //2
cout << "short* :/t" << sizeof(short*) << endl; //4
cout << "short& :/t" << sizeof(short&) << endl; //2
cout << "short[3] :/t" << sizeof(short[3]) << endl; //6
int arr[] ={4,8,9,5,6}; // ia不可改变,可用数组名求其数组大小
int *parr = arr;
cout << "arr :/t" << sizeof(arr) << endl; // 20，是数组名,而不是指针
cout << "parr :/t"<< sizeof(parr) << endl; // 变量,只能求其指针大小//4
cout << "*parr :/t"<<sizeof(*parr) << endl; // 4
char str_c[] ={"china"};
char *p_str = str_c;
cout << "str_c" << sizeof(str_c) << endl; //6 字符串也按数组计算大小
cout << "p_str" << sizeof(p_str) << endl; //4
cout << "*p_str"<< sizeof(*p_str) << endl; // 1
}
@font-face{
font-family:"Times New Roman";
}
@font-face{
font-family:"宋体";
}
@font-face{
font-family:"Symbol";
}
@font-face{
font-family:"Arial";
}
@font-face{
font-family:"黑体";
}
@font-face{
font-family:"Courier New";
}
@font-face{
font-family:"Wingdings";
}
@font-face{
font-family:"新宋体";
}
@font-face{
font-family:"Courier New CYR";
}
p.0{
margin:0pt;
margin-bottom:0.0001pt;
layout-grid-mode:char; text-align:justify;
font-size:10.5000pt; font-family:'Times New Roman'; }
div.Section0{
margin-top:72.0000pt;
margin-bottom:72.0000pt;
margin-left:90.0000pt;
margin-right:90.0000pt;
size:612.0000pt 792.0000pt;
}
在32位操作系统中,基本数据类型
类型 字节长度
char 1
short 2
short int 2
signed short 2
unsigned short 2
int 4
long int 4
signed int 4
unsigned int(unsigned) 4
long 4
unsigned long 4
float 4
double 8
void* 4 (所有指针类型长度都一样)(char*,int*,float*,double*)
enum 4