实现cin>>complex

basic_istream_char* __cdecl basic_istream_char_read_complex_double(basic_istream_char *this, complex_double *v)
{
    double r;
    basic_ios_char *base = basic_istream_char_get_basic_ios(this);


    TRACE("(%p %p)\n", this, v);//wine里用来追踪变量的，功能跟printf差不多
    
     /* 因为正确的格式里只有real 和 (real)还有(real,imaginary)，所以只会在流里取相应字符 */


    ws_basic_istream_char(this);//先用ws()将流里开头的空白都去掉
    //用peek()看看流里第一个字符是什么，不取出来
    if(basic_istream_char_peek(this) == '(') {
        char c;
        basic_istream_char_get(this);//用get()取流第一个字符'(',不保存（因为不需要）
        basic_istream_char_read_double(this, &r);//读流里的double


        if(ios_base_fail(&base->base))//如果不是double类型，返错退出
            return this;


        ws_basic_istream_char(this);//接着又用ws()去掉接下来的空格（' ','\t'）
        c = basic_istream_char_peek(this);//用peek()把字符存到c，但不从流里取出
        if(c == ',') {
            double i;
            basic_istream_char_get(this);//字符是',',complex正常格式，取出
            basic_istream_char_read_double(this, &i);//继续读double


            if(ios_base_fail(&base->base))//返回
                return this;


            ws_basic_istream_char(this);//继续去空格
            c = basic_istream_char_peek(this);//用法同上
            if(c == ')') {
               /* 格式(real, imag) 所以get从流里取走'('*/
                basic_istream_char_get(this);
                v->real = r;
                v->imag = i;
            }else {
                basic_ios_char_setstate(base, IOSTATE_failbit);
                return this;
            }
        }else if(c == ')') {
            /* 格式 (real) */
            basic_istream_char_get(this);
            v->real = r;
            v->imag = 0;
        }else {
            basic_ios_char_setstate(base, IOSTATE_failbit);
            return this;
        }
    }else {
       /* 格式 real */
        basic_istream_char_read_double(this, &r);


        if(ios_base_fail(&base->base))
            return this;
        //如果是(12)这样的格式，只是取实数，虚数为0
        v->real = r;
        v->imag = 0;
    }


    return this;
}