单引号内存放多个字符

int main()
{
    char c = 'abc7';
    DWORD x = 'abc7';
    //int y = 'abc7d'; //该句编译出错;

    cout<<c<<endl;    //7 
    cout<<x<<endl;    //1633837879
    cout<<sizeof('abc7')<<endl; //4
    cout<<sizeof('abc')<<endl;  //4
    cout<<sizeof('ac')<<endl;   //4
    cout<<sizeof('a')<<endl;    //1

    system("pause");
    return 0;
}

An ordinary character literal that contains more than one c-char is a multicharacter literal. A multicharacter literal has type int and implementation-defined value.

单引号内最多存4个字符，超过4个就会编译报错，字符数目个数为2，3，4时单引号内数据占用空间都为4字节。

一般用作tag，单引号内写4个字符 。比如数据序列化到文件中的时候，作为一段数据块的tag标识。

WriteChunkHeader('TEX0');

WriteInt(tex_num);

WriteChunk(...);

WriteChunkHeader('TEX0');