Check whether a Cstring contains only Chinese characters

问题

I am checking whether a CString variable contains only] Chinese characters. The Unicode range for Chinese characters is 4E00 - 9FFF.

I am doing as follows:

CString str;
char ch;
GetDlgItemText( IDC_EDIT1, str );

for(int i=0;i<str.GetLength();i++) {
  ch=str[i];
  if(ch>='\u4E00'&&ch<='\u9FFF') {
  //even if input chinese character here 'if' evaluates to false
    SetDlgItemText( IDC_RICHEDIT21, str );
    SendDlgItemMessage( IDC_RICHEDIT21, EM_REPLACESEL, TRUE, (LPARAM)(LPCTSTR)str);
  } else
    break;

But if I do

if(ch=='\u4E00')

and input the symbol of \u4E00 then it works fine.

So my question is, how to find weather a character lies between a particular Unicode range?

One more thing: if I use if(ch=='\u4e00') then it gives true, but if I do if(ch<='\u4e00') it returns false. I don't understand this behavior!

My code is

CString str;
wchar_t ch;
GetDlgItemText( IDC_EDIT1, str );
for(int i=0;i<str.GetLength();i++) {
  ch=str[i];
  if(ch<='\u4e01') {
    //returns false,  but returns true if(ch=='\u4e01')
    SetDlgItemText( IDC_RICHEDIT21, str );
    SendDlgItemMessage( IDC_RICHEDIT21, EM_REPLACESEL, TRUE, (LPARAM)(LPCTSTR)str);
  else
    break;
}

回答1:

Chinese character ranges:

U+3400 - U+4DB5
U+4E00 - U+62FF
U+6300 - U+77FF
U+7800 - U+8CFF
U+8D00 - U+9FCC
U+20000 - U+215FF
U+21600 - U+230FF
U+23100 - U+245FF
U+24600 - U+260FF
U+26100 - U+275FF
U+27600 - U+290FF
U+29100 - U+2A6DF
U+2A700 - U+2B734
U+2B740 - U+2B81D

You'll have to check all these ranges to be complete and thorough.

回答2:

The range of "char" type is -128~127 or 0~255 depending on your compiler. You should use "wchar_t" or "unsigned short" to make it range from 0 to 65535 or the varible cannot represent that unicode chars.

Btw, you should not place SetDlgItemText and SendDlgItemMessage in that "if" block. define variable "i" before "for" and check if the value of i equals str.Length() after loop.

回答3:

I got the answer. It can be compared as follows:

CString str;
wchar_t ch;
GetDlgItemText( IDC_EDIT1, str );

for(int i=0;i<str.GetLength();i++) {
  ch=str[i];
  if((unsigned int)ch>=0x4E00u&&(unsigned int)ch<=ox9FFFu) {
    SetDlgItemText( IDC_RICHEDIT21, str);
    SendDlgItemMessage( IDC_RICHEDIT21, EM_REPLACESEL, TRUE, (LPARAM)(LPCTSTR)str);
  } else
    break;

来源：https://stackoverflow.com/questions/16228329/check-whether-a-cstring-contains-only-chinese-characters

标签

c++

unicode

mfc

operators