MFC笔记8

1.在循环使用数组时需要清理数组

　　CString str;

　　memset(str,0,strlen(str));

判断两个字符串包含数字大小是否相等

　　CString str="22";

　　if(str!="22"){}

2.读取文件

//2.读人员文件renyuan.txt
HANDLE rFile;
    DWORD dwRet;
    memset(str,0,2000);
    rFile = CreateFile(_T("\\NANDFlash\\renyuan.txt"),GENERIC_READ ,0,NULL,OPEN_EXISTING,0,NULL);
    if(rFile == INVALID_HANDLE_VALUE)
    {
         AfxMessageBox(_T("打开失败"));
         return false;
    }else{
            
        ReadFile(rFile,str,5000,&dwRet,NULL);
        ss=str;
        do{
            index = ss.Find( ';' );
            temp=ss.Left( index ) ;
            n = temp.Find( ':' );
            renyuan_name[num_renyuan]=temp.Left(n);
            arr=temp.Right( temp.GetLength( )-n-1 ) ;
            m = arr.Find( ',' );
            renyuan_gonghao[num_renyuan]=arr.Left(m);
            renyuan_danwei[num_renyuan]=arr.Right( arr.GetLength( )-m-1 ) ;
            ss=ss.Right( ss.GetLength( )-index-1 );    
            num_renyuan++;
        }while(ss.Find( ';' )!=-1);
    }
    CloseHandle(rFile);

或者

memset(str,0,2000);
	num_renyuan=0;
	hFile =file.Open(_T("\\NANDFlash\\renyuan.txt"),CFile::modeRead );
	if(hFile == -1){
		AfxMessageBox(_T("file open error\n"));      
	}
	file.Read(str, 2000);
	ss=str;
	do{
	index = ss.Find( ';' );
	temp=ss.Left( index ) ;
	n = temp.Find( ':' );
	renyuan_name[num_renyuan]=temp.Left(n);
	arr=temp.Right( temp.GetLength( )-n-1 ) ;
	m = arr.Find( ',' );
	renyuan_gonghao[num_renyuan]=arr.Left(m);
	renyuan_danwei[num_renyuan]=arr.Right( arr.GetLength( )-m-1 ) ;
	ss=ss.Right( ss.GetLength( )-index-1 );	
	num_renyuan++;

	}while(ss.Find( ';' )!=-1);
	file.Close();

　　写文件代码：

//写入数据
		HANDLE hFile;
		DWORD dwRet;

		char str[2000];

		hFile = CreateFile(_T("\\NANDFlash\\renyuan.txt"),GENERIC_READ | GENERIC_WRITE,0,NULL,TRUNCATE_EXISTING,0,NULL);

		if(hFile == INVALID_HANDLE_VALUE)
		{
			 AfxMessageBox(_T("打开失败"));
			
		}else{
			if(MessageBox(_T("确认删除用户，密码？"),_T("提示"),MB_OKCANCEL)==1)	
			{
				int i,j;
				//1.先将数据更新到数组，
				for(i=0,j=0;i<num_renyuan;i++,j++)
				{
		
					if(i<flag||i>flag){
						renyuan_name[j]=renyuan_name[i];
						renyuan_gonghao[j]=renyuan_gonghao[i];
						renyuan_danwei[j]=renyuan_danwei[i];
					}else if(i==flag){
						i++;
						renyuan_name[j]=renyuan_name[i];
						renyuan_gonghao[j]=renyuan_gonghao[i];
						renyuan_danwei[j]=renyuan_danwei[i];
					}
				}
				num_renyuan--;
				//2.然后将数据从数组更新到文件中
				for(i=0;i<num_renyuan;i++)
				{
					CString temp;//将temp清零
					temp+=renyuan_name[i];
					temp+=":";
					temp+=renyuan_gonghao[i];
					temp+=",";
					temp+=renyuan_danwei[i];
					temp+=";";
					sprintf(str,"%S",temp);//S这样str就是完整的"username:passwors;",如果换成s，只会将一个字符传给str
					WriteFile(hFile, str, strlen(str),&dwRet,NULL);		
				}
				CloseHandle(hFile);
				OnOK();
			}
		}