{"id":211,"date":"2010-04-28T20:04:23","date_gmt":"2010-04-28T20:04:23","guid":{"rendered":"https:\/\/ibex.tech\/visualcpp\/?p=211"},"modified":"2022-02-17T06:24:05","modified_gmt":"2022-02-17T06:24:05","slug":"working-with-strings","status":"publish","type":"post","link":"https:\/\/ibex.tech\/visualcpp\/strings\/working-with-strings","title":{"rendered":"Working With Strings"},"content":{"rendered":"

\nString Special Characters
\n<\/h4>\n
\r\n\r\nsTemp += "\\r\\n"\t\t\/\/Add a newline\r\nString ^sTemp =  = "\\x7";\t\/\/ ‘\\x’ means ‘0x’ and the 1 of 2 digits that follow are a hex value for the character requried\r\n\r\n\tnewline( LF)\t\t\\n\t\thorizontal tab (TAB)\t\\t\r\n\tvertical tab\t\t\\v\t\tbackspace\t\t\\b\r\n\tcarriage return (CR)\t\\r\t\tformfeed\t\t\\f\r\n\talert (bell)\t\t\\a\t\tbackslash\t\t\\\\\r\n\tquestion mark\t\t\\?\t\tsingle quote\t\t\\'\r\n\tdouble quote\t\t\\"\t\tnull (NULL)\t\t\\0\r\n<\/code><\/pre>\n
\nYou can do this:
\nMyString = "\\x1b" "N" "\\x1"; \/\/N<1>\n<\/p>\n
\nLength
\n<\/h4>\n
\r\n\r\n\tint Count = myString->Length;\r\n<\/code><\/pre>\n
\nRemoving spaces (or other characters) from beginning and end of a string
\n<\/h4>\n
\r\n\r\n\tMyString = MyString->Trim();\r\n<\/code><\/pre>\n
\nRead Characters Within A String
\n<\/h4>\n
\r\n\r\n\tString ^MyString;\r\n\r\n\tChar a = Convert::ToChar(MyString[3]);\r\n\r\n\tif (Convert::ToChar(MyString[1]) != '.')\r\n<\/code><\/pre>\n
\nFind First Instance Of
\n<\/h4>\n
\r\n\r\n\tIndex = TempString->IndexOf("\\\\");\r\n<\/code><\/pre>\n
\nFind Last Instance Of
\n<\/h4>\n
\r\n\r\n\tIndex = TempString->LastIndexOf("\\\\");\r\n<\/code><\/pre>\n
\nGet string from character position # (Remove text from beginning or end of string)
\n<\/h4>\n
\nGetting beginning of a string
\n<\/h5>\n
\r\n\r\n\tif (TempString->LastIndexOf("\\\\") >= 0)\r\n\t\tTempString = TempString->Substring(0, (TempString->LastIndexOf("\\\\")));\r\n<\/code><\/pre>\n
\nGetting end of string
\n<\/h5>\n
\r\n\r\n\tif (TempString->LastIndexOf("\\\\") >= 0)\r\n\t\tTempString = TempString->Substring(TempString->LastIndexOf("\\\\") + 1);\r\n<\/code><\/pre>\n
\nGet Characters Between Markers Within String
\n<\/h4>\n
\r\n\r\n\tString ^StartAfterChars;\r\n\tString ^EndBeforeChars;\r\n\tint Start;\r\n\tint Length;\r\n\r\n\tStartAfterChars = "?a=";\r\n\tEndBeforeChars = "&b=";\r\n\tStart = sTemp->IndexOf(StartAfterChars) + StartAfterChars->Length;\r\n\tLength = sTemp->IndexOf(EndBeforeChars) - Start;\r\n\tif ((Start > 0) && (Length > 0))\r\n\t\tUserId = sTemp->Substring(Start, Length);\r\n\telse\r\n\t\tUserId = "";\r\n<\/code><\/pre>\n
\nInsert Into String
\n<\/h4>\n
\r\n\tmyString->Insert(0, "1234");\t\/\/Insert at character 0<\/code><\/pre>\n
\nReplace Characters In String
\n<\/h4>\n
\r\n\r\n\tmyString->Replace(".", "!");\t\/\/Replace all . with !\r\n\tsTemp = sTemp->Replace('A', 'B');\t\/\/Replace a with B\r\n\tsTemp = sTemp->Replace("RemoveMe", "ReplaceWitMe");\r\n<\/code><\/pre>\n
\nAppend To End Of String
\n<\/h4>\n
\r\n\r\n\tmyString->Append("1234");\r\n\tmyString->Append(gcnew array{'+', '+'});\r\n<\/code><\/pre>\n
\nDoes string contain #
\n<\/h4>\n
\r\n\r\n\tif (MyString->Contains("ABCDEFG"))\r\n<\/code><\/pre>\n
\nValidating Text String Entry
\n<\/h4>\n
\r\n\r\n\tMyString = MyString->Trim();\t\t\/\/Remove leading or trailing spaces\r\n\tif (myString->Length > 30)\r\n\t\tmyString = myString->Substring(0, 29);\r\n\r\n\t\/\/Use these to force case:-\r\n\t\/\/MyString = MyString->ToLower\r\n\t\/\/MyString = MyString->ToUpper\r\n<\/code><\/pre>\n
\nValidating Numeric String Entry
\n<\/h4>\n
\nCheck for integer value entered
\n<\/h5>\n
\r\n\r\n\tString ^ValueEntered;\r\n\tValueEntered = txtMyTextBox->Text;\r\n\tValueEntered= ValueEntered->Trim();\t\t\t\t\/\/Remove leading and trailing spaces\r\n\tif (\r\n\t(ValueEntered->Length < 1) ||\r\n\t(!System::Text::RegularExpressions::Regex::IsMatch(ValueEntered, "^[0-9]*$"))\r\n\t)\r\n\t\t\/\/Value is not numeric\r\n<\/code><\/pre>\n
\nCheck for general numberic value entered
\n<\/h5>\n
\nUse one of the solutions below as the best regex expression I have found is:\n<\/p>\n
\r\n\t\t"^[-0-9]*.[.0-9].[0-9]*$"<\/code><\/pre>\n
\nThis is greate if you ensure the string as at least 3 digits long by adding leading zero's, but it will let through multiple '.' being entered.\n<\/p>\n
\nAn alternative solution uses a try, catch approach which isn't nearly as nice
\n<\/h5>\n
\r\n\r\nInt32 myInt = 0;\r\ntry\r\n{\r\n\tmyInt = System::Convert::ToInt32 (myTextBox->Text);\r\n}\r\ncatch (System::FormatException * pEx)\r\n{\r\n\tmyInt = 0; \/\/ or another default value\r\n}\r\ncatch (System::OverflowException * pEx)\r\n{\r\n\tmyInt = 0; \/\/ or another default value\r\n}\r\n<\/code><\/pre>\n
\nYou could use the VB IsNumeric function by doing this, but not a 'nice' approach as you have to reference another dll
\n<\/h5>\n
\r\n\r\n\t#using\r\n\t...\r\n\t...\r\n\tif ( Microsoft::VisualBasic::Information::IsNumeric ( myTextBox->Text ) )\r\n\t   myInt = System::Convert::ToInt32 ( myTextBox->Text );\r\n\telse\r\n\t   MessageBox::Show ( "Value not numeric" );\r\n<\/code><\/pre>\n
\nThere are lots of other tests in the String class
\n<\/h4>\n
\nIndexOf Overloaded. Reports the index of the first occurrence of a String, or one or more characters, within this string.
\nIndexOfAny Overloaded. Reports the index of the first occurrence in this instance of any character in a specified array of Unicode characters.
\nLastIndexOf Overloaded. Reports the index position of the last occurrence of a specified Unicode character or String within this instance.
\nLastIndexOfAny Overloaded. Reports the index position of the last occurrence in this instance of one or more characters specified in a Unicode array.\n<\/p>\n
\n <\/p>\n","protected":false},"excerpt":{"rendered":"
String Special Characters sTemp += "\\r\\n" \/\/Add a newline String ^sTemp = = "\\x7"; \/\/ ‘\\x’ means ‘0x’ and the 1 of 2 digits that follow are a hex value for the character requried newline( LF) \\n horizontal tab (TAB) \\t vertical tab \\v backspace \\b carriage return (CR) \\r formfeed \\f alert (bell) \\a […]<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[],"class_list":["post-211","post","type-post","status-publish","format-standard","hentry","category-strings"],"_links":{"self":[{"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/posts\/211","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/comments?post=211"}],"version-history":[{"count":16,"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/posts\/211\/revisions"}],"predecessor-version":[{"id":923,"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/posts\/211\/revisions\/923"}],"wp:attachment":[{"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/media?parent=211"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/categories?post=211"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ibex.tech\/visualcpp\/wp-json\/wp\/v2\/tags?post=211"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}