string,char,char*,char a[] 占字节数, 以及sizeof,strlen(),str.length()的用法

// studystring.cpp :
//

#include "stdafx.h"
#include
#include
using namespace std;

int main(int argc, char* argv[])
{

    cout<<"char,char*,string 在C++中的占几个字节: -------------------------"<
    cout<<"sizeof(char) = "<<sizeof(char)<//=1
    cout<<"sizeof(char*) = "<<sizeof(char*)<//=4
    cout<<"sizeof(string) = "<<sizeof(string)<//=16
    cout<<"----------------------------------------------------------------"<
    cout<

    string str;
    str = "12345678912"; // 11个字符
    cout<<"the size of str = "<<sizeof(str)<// = 16
    cout<<"the length of str = "<// = 11
    cout<<"----------------------------------------------------------------"<
    cout<

    //--
    char* ch = "12345678912"; // 11个字符
    cout<<"the size of ch = "<<sizeof(ch)<// = 4
    cout<<"the length of ch = "<// = 11
    cout<<"----------------------------------------------------------------"<
    cout<

    //--

    char a[]="12345678912"; // 11个字符
    cout<<"the size of a = "<<sizeof(a)<// = 12,包括了字符串结束符'\0'
    cout<<"the length of a = "<//=11
    cout<<"----------------------------------------------------------------"<
    cout<

    //--
    char chr[12]="12345678912"; // 11个字符     char chr[11]="12345678912"; 编译报错 array bounds overflow
    cout<<"the size of chr = "<<sizeof(chr)<// =12
    cout<<"the length of chr = "<// =11
    cout<<"----------------------------------------------------------------"<
    cout<

    //--
    char chrr[100]="12345678912"; // 11个字符
    cout<<"the size of chrr = "<<sizeof(chrr)<// =100
    cout<<"the length of chrr = "<// =11
    cout<<"----------------------------------------------------------------"<
    cout<

    //--
    char strr[8]={'a'};
    cout<<"the size of strr = "<<sizeof(strr)<// =8
    cout<<"the length of strr = "<// =1
    cout<<"----------------------------------------------------------------"<
    cout<

    return 0;
}