一个时间格式的字符串转为SYSTEMTIME的奇怪问题

[starytx]

CString str("2021-03-08 14:19:30:245");
SYSTEMTIME st;
sscanf(str, "%04u-%02u-%02u %02u:%02u:%02u.%03u", &st.wYear,%st.wMonth, &st.wDay,&st.wHour,&st.wMinute,&st.wSecond,&st.wMilliseconds);

上边这段代码跑起来有问题，必须如果放在一个对话框的OnInitDialog里的话，对话框显示不出来。
最后的毫秒数得专门定义一个变量来接收，然后再赋值给st结构中的毫秒才可以，不知道为啥会这样？

[starytx]

补充一下是vc6开发环境

[forever74]

因为你在字符串里敲了冒号，却在格式串里敲了点。

[starytx]

引用 2 楼 forever74 的回复:

因为你在字符串里敲了冒号，却在格式串里敲了点。

这个是笔误，问题找到了，是要用%hu

[赵4老师]

CString str("2021-03-08 14:19:30:245"); SYSTEMTIME st; sscanf(str, "%04u-%02u-%02u %02u:%02u:%02u.%03u", &st.wYear,%st.wMonth, &st.wDay,&st.wHour,&st.wMinute,&st.wSecond,&st.wMilliseconds);

[赵4老师]

上面是: 下面是. 废眼睛

[starytx]

引用 5 楼 赵4老师 的回复:

上面是: 下面是. 废眼睛

老赵也错了，是格式化符号的问题，WORD要用%hu

[赵4老师]

//typedef struct _SYSTEMTIME {
//  WORD wYear;
//  WORD wMonth;
//  WORD wDayOfWeek;
//  WORD wDay;
//  WORD wHour;
//  WORD wMinute;
//  WORD wSecond;
//  WORD wMilliseconds;
//} SYSTEMTIME;

CString str(
"2021"  //wYear
"-03"   //wMonth
"-08"   //wDay
" 14"   //wHour
":19"   //wMinute
":30"   //wSecond
".245"  //wMilliseconds
);
SYSTEMTIME st;
if (7!=sscanf(str,
    "%4u"   //wYear
    "-%2u"  //wMonth
    "-%2u"  //wDay
    " %2u"  //wHour
    ":%2u"  //wMinute
    ":%2u"  //wSecond
    ".%3u", //wMilliseconds
    &st.wYear,
    &st.wMonth,
    &st.wDay,
    &st.wHour,
    &st.wMinute,
    &st.wSecond,
    &st.wMilliseconds)) {
    printf(
        "YYYY"  //wYear
        "-MM"   //wMonth
        "-DD"   //wDay
        " hh"   //wHour
        ":mm"   //wMinute
        ":ss"   //wSecond
        ".mss"  //wMilliseconds
        " format sscanf fail in str[%s]\n",str);
}

[赵4老师]

对，是要用%hu

//typedef struct _SYSTEMTIME {
//  WORD wYear;
//  WORD wMonth;
//  WORD wDayOfWeek;
//  WORD wDay;
//  WORD wHour;
//  WORD wMinute;
//  WORD wSecond;
//  WORD wMilliseconds;
//} SYSTEMTIME;

CString str(
"2021"  //wYear
"-03"   //wMonth
"-08"   //wDay
" 14"   //wHour
":19"   //wMinute
":30"   //wSecond
".245"  //wMilliseconds
);
SYSTEMTIME st;
if (7!=sscanf(str,
    "%4hu"   //wYear
    "-%2hu"  //wMonth
    "-%2hu"  //wDay
    " %2hu"  //wHour
    ":%2hu"  //wMinute
    ":%2hu"  //wSecond
    ".%3hu", //wMilliseconds
    &st.wYear,
    &st.wMonth,
    &st.wDay,
    &st.wHour,
    &st.wMinute,
    &st.wSecond,
    &st.wMilliseconds)) {
    printf(
        "YYYY"  //wYear
        "-MM"   //wMonth
        "-DD"   //wDay
        " hh"   //wHour
        ":mm"   //wMinute
        ":ss"   //wSecond
        ".mss"  //wMilliseconds
        " format sscanf fail in str[%s]\n",str);
}

[赵4老师]

printf里面的%和变量的一一对应关系 scanf里面的%和变量以及变量前加不加&的一一对应关系 是C代码中非常容易出错的地方，而且通常编译还不出错。 所以在编译源代码之前值得专门仔细检查一遍甚至多遍。