match_results begin() and end() function in C++ STL Last Updated : 11 Jul, 2025 Comments Improve Suggest changes Like Article Like Report match_results::cbegin() is an inbuilt function in C++ STL that returns an iterator that points to the first match in the match_results object. Syntax: smatch_name.begin()Parameters: This function does not accept any parameters. Return value: This function returns an iterator pointing to the first match in the match_results object. The matches contained in the match_results object are always constant. Note: The first element always contains the whole regex match while the others contain the particular Capturing Group. Below program illustrate the above function: CPP // C++ program to illustrate the // match_results begin() function #include <bits/stdc++.h> using namespace std; int main() { string sp("geeksforgeeks"); regex re("(geeks)(.*)"); smatch match; // we can use member function on match // to extract the matched pattern. std::regex_match(sp, match, re); // The size() member function indicates the // number of capturing groups plus one for the overall match // match size = Number of capturing group + 1 // (.*) which "forgeeks" ). cout << "Match size = " << match.size() << endl; cout << "matches:" << endl; for (smatch::iterator it = match.begin(); it != match.end(); ++it) cout << *it << endl; return 0; } Output: Match size = 3 matches: geeksforgeeks geeks forgeeks match_results::end() is an inbuilt function in C++ STL that returns an iterator that points to the past-the-end match in the match_results object. Syntax: smatch_name.end() Parameters: This function does not accept any parameters. Return value: This function returns an iterator pointing to the past-the-end match in the match_results object. The matches contained in the match_results object are always constant. Note: First element always contains the whole regex match while the others contain the particular Capturing Group. Below program illustrate the above function CPP // C++ program to illustrate the // match_results end() function #include <bits/stdc++.h> using namespace std; int main() { string sp("matchresult"); regex re("(match)(.*)"); smatch match; // we can use member function on match // to extract the matched pattern. std::regex_match(sp, match, re); // The size() member function indicates the // number of capturing groups plus one for the overall match // match size = Number of capturing group + 1 // (.*) which "results" ). cout << "Match size = " << match.size() << endl; cout << "matches:" << endl; for (smatch::iterator it = match.begin(); it != match.end(); ++it) cout << *it << endl; return 0; } Output: Match size = 3 matches: matchresult match result Let us see the differences in a tabular form as follows: match_results begin()match_results end()It is used to return an iterator pointing to the first match in the match_results object.It is used to return an iterator pointing to the past-the-end match in the match_results object. Its syntax is -: const_iterator begin() const; Its syntax is -: const_iterator end() const;It does not take any parameters.It does not take any parameters.Its complexity is constant.Its complexity is constant.Its iterator validity does not change.Its iterator validity does not change. Comment More infoAdvertise with us Next Article Introduction to C++ Programming Language H Harsha_Mogali Follow Improve Article Tags : Misc C++ STL CPP-Functions cpp-class CPP-regex +2 More Practice Tags : CPPMiscSTL Similar Reads C++ Programming Language C++ is a computer programming language developed by Bjarne Stroustrup as an extension of the C language. It is known for is fast speed, low level memory management and is often taught as first programming language. It provides:Hands-on application of different programming concepts.Similar syntax to 5 min read C++ OverviewIntroduction to C++ Programming LanguageC++ is a general-purpose programming language that was developed by Bjarne Stroustrup as an enhancement of the C language to add object-oriented paradigm. It is considered as a middle-level language as it combines features of both high-level and low-level languages. It has high level language featur 3 min read Features of C++C++ is a general-purpose programming language that was developed as an enhancement of the C language to include an object-oriented paradigm. It is an imperative and compiled language. C++ has a number of features, including:Object-Oriented ProgrammingMachine IndependentSimpleHigh-Level LanguagePopul 5 min read History of C++The C++ language is an object-oriented programming language & is a combination of both low-level & high-level language - a Middle-Level Language. 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These two ways are generally differentiated by the type of values passed to them as parameters.The following table lists the differences between the call-by-value and call-by-reference methods of parameter passing.Call By Valu 4 min read Default Arguments in C++A default argument is a value provided for a parameter in a function declaration that is automatically assigned by the compiler if no value is provided for those parameters in function call. If the value is passed for it, the default value is overwritten by the passed value.Example:C++#include <i 5 min read Inline Functions in C++In C++, inline functions provide a way to optimize the performance of the program by reducing the overhead related to a function call. When a function is specified as inline the whole code of the inline function is inserted or substituted at the point of its call during the compilation instead of us 6 min read Lambda Expression in C++C++ 11 introduced lambda expressions to allow inline functions which can be used for short snippets of code that are not going to be reused. Therefore, they do not require a name. They are mostly used in STL algorithms as callback functions.Example:C++#include <iostream> using namespace std; i 4 min read C++ Pointers and ReferencesPointers and References in C++In C++ pointers and references both are mechanisms used to deal with memory, memory address, and data in a program. Pointers are used to store the memory address of another variable whereas references are used to create an alias for an already existing variable. Pointers in C++ Pointers in C++ are a 5 min read C++ PointersA pointer is a special variable that holds the memory address of another variable, rather than storing a direct value itself. Pointers allow programs to access and manipulate data in memory efficiently, making them a key feature for system-level programming and dynamic memory management. When we acc 8 min read Dangling, Void , Null and Wild Pointers in CIn C programming pointers are used to manipulate memory addresses, to store the address of some variable or memory location. But certain situations and characteristics related to pointers become challenging in terms of memory safety and program behavior these include Dangling (when pointing to deall 6 min read Applications of Pointers in CPointers in C are variables that are used to store the memory address of another variable. Pointers allow us to efficiently manage the memory and hence optimize our program. In this article, we will discuss some of the major applications of pointers in C. Prerequisite: Pointers in C. C Pointers Appl 4 min read Understanding nullptr in C++Consider the following C++ program that shows problem with NULL (need of nullptr) CPP // C++ program to demonstrate problem with NULL #include <bits/stdc++.h> using namespace std; // function with integer argument void fun(int N) { cout << "fun(int)"; return;} // Overloaded fun 3 min read References in C++In C++, a reference works as an alias for an existing variable, providing an alternative name for it and allowing you to work with the original data directly.Example:C++#include <iostream> using namespace std; int main() { int x = 10; // ref is a reference to x. int& ref = x; // printing v 5 min read Can References Refer to Invalid Location in C++?Reference Variables: You can create a second name for a variable in C++, which you can use to read or edit the original data contained in that variable. While this may not sound appealing at first, declaring a reference and assigning it a variable allows you to treat the reference as if it were the 2 min read Pointers vs References in C++Prerequisite: Pointers, References C and C++ support pointers, which is different from most other programming languages such as Java, Python, Ruby, Perl and PHP as they only support references. But interestingly, C++, along with pointers, also supports references. On the surface, both references and 5 min read Passing By Pointer vs Passing By Reference in C++In C++, we can pass parameters to a function either by pointers or by reference. In both cases, we get the same result. So, what is the difference between Passing by Pointer and Passing by Reference in C++?Let's first understand what Passing by Pointer and Passing by Reference in C++ mean:Passing by 5 min read When do we pass arguments by pointer?In C, the pass-by pointer method allows users to pass the address of an argument to the function instead of the actual value. This allows programmers to change the actual data from the function and also improve the performance of the program. In C, variables are passed by pointer in the following ca 5 min read Like