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How To Make find_first_not_of() String Searches In A C++ App

How To Make find first not of String Searches In A C++ App

How can I find a first or last character that is not a character that i am searching in a string in my C++ app? What kind of methods I can use to find the first character equal to none of the characters in the given string in a std::string? How can I use find_first_not_of(), find_last_not_of() methods with strings?

Modern C++ uses Wide Strings and Unicode Strings to support worldwide languages. Wide Strings (std::wstring) uses wcha_tr as the character type which means they are 2-bytes chars and they are an instantiation of the basic_string class template. In C++, there are several type definitions for common character types and one of them is std::wstring types that are defined in header <string>.

What is a wstring in a C++ app?

wstrings are the string class for 2-bytes characters represented with wstring and alphanumeric characters are stored and displayed in wide string forms. In other terms, wstring stores for the alphanumeric text with 2-byte chars, called wchar_t. Wide Strings are the instantiation of the basic_string class template that uses wchar_t as the character type. In modern C++, simply we can define a wide string with L” ” literal as below,

Wide Strings (wstring) are a class that contains arrays of wide characters with useful methods, and we can access, or modify their characters easily. Note that, In C++, while wide string contents are defined between L” and with literal L, wide characters are defined between L’ and with literal L

The wstring has methods to append, assign, copy, align, replace or operate with other wide strings. These methods can be used in all string methods with their appropriate syntax. We can find the first or last character equal to none of the characters in the given string by using find_first_not_of() and find_last_not_of() methods.

How to search a wide string with the find_first_not_of() method in a C++ app

The find_first_not_of() Method is a String Method that searches given character in this method and finds the first character position from the wide string that is not a given character. In another term, the find_first_not_of() method finds the first character equal to none of the characters in the given wide string or character sequence. If the character is not present method returns the npos of the wstring (std::string::npos).

Simply we can find the first character equal to none of the characters in the given wstring by using its find_first_not_of() method as given syntax.

Syntax:

A full C++ app example of using the find_first_not_of() method to search a wstring

Here we can find a character of a wstring in another wstring by using its find_first_not_of() method as given full example below.

Output of this code will be as below,

as you see we find the first character after the ‘-‘ characters in our wstring

How to search a wide string with the find_last_not_of() method in C++

The find_last_not_of() Method is a String Method that search given character in this method and finds the last character position from wide string that is not a given character. In another term, find_last_not_of() method finds the last character equal to none of the characters in the given wide string or character sequence. If the character is not present method returns the npos of the wstring (std::string::npos).

Simply we can find the last character equal to none of the characters in the given wstring by using its find_last_not_of() method as given syntax.

Syntax:

A full example of using the find_last_not_of() method to search a wstring in a C++ app

Here we can find a character of a wstring in another wstring by using its find_last_not_of() method as given full example below.

Output of this code will be as below,

as you see we find the last character before the last ‘-‘ characters in our wstring

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About author

33+ years of coding with more than 30+ programming languages, mostly C++ on Windows, Android, Mac-OS, iOS, Linux and some other operating systems. Dr. Yilmaz Yoru was born in 1974, Eskisehir-Turkey. He graduated from the department of Mechanical Engineering of Eskisehir Osmangazi University in 1997. One year later he started to work in the same university as an assistant. He received his MSc and PhD degrees from the same department of the same university. He has married and he is a father of a son. Some of his interests are Programming, Thermodynamics, Fluid Mechanics and Artificial Intelligence. He also likes the graphical 2D & 3D design and high-end innovations.
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