vwprintf() function in C/C++ Last Updated : 14 Sep, 2018 Comments Improve Suggest changes Like Article Like Report The vwprintf() function in C++ is used to write a formatted wide string to stdout. It prints formatted data from variable argument list to stdout. Internally, the function retrieves arguments from the list identified by arg as if va_arg was used on it, and thus the state of arg is likely altered by the call. The wide string format may contain format specifiers starting with % which are replaced by the values of variables that are passed as a list vlist. It is defined in header file <cwchar.h> Syntax : int vwprintf( const wchar_t* format, va_list vlist ) Parameter : The function accepts four mandatory parameters which are described below: format: specifies a pointer to a null terminated wide string that is written to stdout arg: specifies a value identifying a variable arguments list initialized with va_start Return value : The function returns two value as below: On success, the total number of characters written is returned. A negative number is returned if some error is occurred. Below programs illustrate the above function: Program 1 : CPP // C++ program to illustrate the // vwprintf() function // for some english letter #include <bits/stdc++.h> using namespace std; // function to print formatted // data from variable argument list to stdout void write(const wchar_t* format, ...) { // hold the variable argument va_list arg; // A function that invokes va_start // shall also invoke va_end before it returns. va_start(arg, format); vwprintf(format, arg); va_end(arg); } // Driver code int main() { setlocale(LC_ALL, "en_US.UTF-8"); wchar_t buffer[5][10] = { L"First", L"Second", L"Third", L"Fourth", L"Fifth" }; int k = 0; // print letters by calling write function wprintf(L"Some English Letters\n"); for (wchar_t i = L'A'; i <= L'E'; i++) { write(L"%ls : %lc\n", buffer[k], i); k++; } return 0; } Output: Some English Letters First : A Second : B Third : C Fourth : D Fifth : E CPP // C++ program to illustrate the // vwprintf() function // for some Latin letters #include <bits/stdc++.h> using namespace std; // function to print formatted // data from variable argument list to stdout void write(const wchar_t* format, ...) { // hold the variable argument va_list arg; // A function that invokes va_start // shall also invoke va_end before it returns. va_start(arg, format); vwprintf(format, arg); va_end(arg); } // Driver code int main() { setlocale(LC_ALL, "en_US.UTF-8"); wchar_t buffer[5][10] = { L"First", L"Second", L"Third", L"Fourth", L"Fifth" }; int k = 0; // print letters by calling write function wprintf(L"Some Latin Letters\n"); for (wchar_t i = L'\u0021'; i <= L'\u0025'; i++) { write(L"%ls : %lc\n", buffer[k], i); k++; } return 0; } Output: Some Latin Letters First : ! Second : " Third : # Fourth : $ Fifth : % Comment More infoAdvertise with us Next Article Introduction to C++ Programming Language A AmanSrivastava1 Follow Improve Article Tags : C++ CPP-Library C-Library Practice Tags : CPP 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. The programming language was created, designed & developed by a Danish Computer Scientist - Bjarne Stroustrup at Bell Telephone Laboratories ( 7 min read Interesting Facts about C++C++ is a general-purpose, object-oriented programming language. It supports generic programming and low-level memory manipulation. Bjarne Stroustrup (Bell Labs) in 1979, introduced the C-With-Classes, and in 1983 with the C++. 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It is generally preferred over while and do-while loops in case the number of iterations is known beforehand.Let's take a look at an example:C++#include <bits/stdc++.h 6 min read Range-Based for Loop in C++In C++, the range-based for loop introduced in C++ 11 is a version of for loop that is able to iterate over a range. This range can be anything that is iteratable, such as arrays, strings and STL containers. It provides a more readable and concise syntax compared to traditional for loops.Let's take 3 min read C++ While LoopIn C++, the while loop is an entry-controlled loop that repeatedly executes a block of code as long as the given condition remains true. Unlike the for loop, while loop is used in situations where we do not know the exact number of iterations of the loop beforehand as the loop execution is terminate 3 min read C++ do while LoopIn C++, the do-while loop is an exit-controlled loop that repeatedly executes a block of code at least once and continues executing as long as a given condition remains true. Unlike the while loop, the do-while loop guarantees that the loop body will execute at least once, regardless of whether the 4 min read C++ FunctionsFunctions in C++A Function is a reusable block of code designed to perform a specific task. It helps break large programs into smaller, logical parts. Functions make code cleaner, easier to understand, and more maintainable.Just like in other languages, C++ functions can take inputs (called parameters), execute a b 8 min read return Statement in C++In C++, the return statement returns the flow of the execution to the function from where it is called. This statement does not mandatorily need any conditional statements. As soon as the statement is executed, the flow of the program stops immediately and returns the control from where it was calle 4 min read Parameter Passing Techniques in CIn C, passing values to a function means providing data to the function when it is called so that the function can use or manipulate that data. Here:Formal Parameters: Variables used in parameter list in a function declaration/definition as placeholders. Also called only parameters.Actual Parameters 3 min read Difference Between Call by Value and Call by Reference in CFunctions can be invoked in two ways: Call by Value or Call by Reference. 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