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In this article, we will explore the purpose of using function prototypes in C or C++. What are Function Prototypes? The function prototypes tell the compiler about the number of arguments and the required data types of function parameters; they also tell the compiler about the return type of the function. With this information, the compiler cross-checks the function signatures before calling it. If the function prototypes are not mentioned, then the program may be compiled with some warnings and sometimes generate some strange output. Purpose of a Function Prototype When a function is called before it is defined, and ... Read More
In C++, a pointer stores the address of another variable, which means that the pointer itself does not contain a value of its own. However, you can assign a null value or a 0 to a pointer, in which case the pointer will not point to the address of any other variable. NULL: It is special constant that indicates the pointer does not point to any valid memory location i.e., an Empty Pointer. 0: It is an older way to represent a null pointer to indicate that the pointer points to nothing. nullptr: It is introduced in C++11, it ... Read More
In C++, a vector is a dynamic array provided by the Standard Template Library (STL) that can grow or shrink in size and can store multiple elements of the same type (like int, string, etc.). Instead of accessing elements one by one using indexes like vec[0], vec[1], etc., The C++ provides helper functions like begin() and end() that return iterators. These iterators make it easy to loop through the vector from start to end, especially for loops. The vector::begin() Function The vector::begin() function returns an iterator pointing to the first element of the vector. Syntax vectorname.begin() Parameters This function does ... Read More
The begin() and end() functions are member functions of the std::set container, which is defined in the header file. The std::set in C++ STL (Standard Template Library) always stores its elements in sorted order. So when you use begin() and end() functions, the elements in the set, which are automatically arranged in sorted order (from smallest to largest by default) retrieve the smallest as the first element and largest as the last element. The begin() and end() functions are used to loop through all elements of the set. The std::set uses bidirectional iterators, where you can: ... Read More
Appending text means adding new content to an existing file without removing its current content. In C++, this can be done by opening the file in append mode and writing the specified content to it. Steps to Append Text to a Text File You need to follow the below steps to open a file in append mode and append the content to it: First of all, you need to include the header file. Them, create an ofstream object to write to the file. Open the file in append mode using the ios::app flag. Use the
In C++, a std::vector is a container that is a part of the STL (Standard Template Library). It enables dynamic arrays which can adjust their size automatically. Depending on the requirements and version of C++ being used, there are many ways to initialize a std::vector with hardcoded elements. Initializing a std::vector with Hardcoded Elements Some of the approaches to initialize a std::vector with hardcoded elements in C++: Using Initializer List Using assign() Function Using accumulate() function Initializing Vector Using Initializer List An initializer list is a ... Read More
In C++, declaration and definition are often confused. A declaration tells the compiler about the name and type, while a definition allocates memory or provides implementation. In this article, we will understand their differences with examples. What is a Declaration in C++? A declaration means (in C or C++) that you are telling the compiler about type, size and in case of function declaration, type and size of its parameters of any variable, or user-defined type or function in your program. No space is reserved in memory for any variable in case of the declaration. Following is the syntax to ... Read More
In this article, we have an unsorted array of integers having repetitive elements. Our task is to count the distinct elements in the given array in C++. Example Here is an example of counting the unique number in the given array: Input: array = {4, 2, 32, 26, 57, 52, 40, 2, 57, 40, 33} Output: Distinct elements in the array: 8 Here is a list of approaches for counting distinct elements in the given array: Using Nested for Loop Using Sorting ... Read More
In this article, we will explain the 4 color problem to color a graph and implement the backtracking algorithm to solve it in C++. The 4 Color Problem The 4-color problem states that the maximum number of colors needed to color any planar graph (or a 2D map) is four, such that no two adjacent nodes have the same color. For example, suppose that you want to color a world map, such that no two countries sharing a border have the same color. According to this theorem, the maximum number of colors needed to do this is four. Now, ... Read More
In this article, we will solve a sum array puzzle, where we have an array with n elements. We have to create another array of n elements such that the 'ith' position of the second array will hold the sum of all elements of the first array except the 'ith' element. We have one constraint, we cannot use the subtraction operator in this problem. Example Here is an example of calculating the sum of array elements except for the ith element: Input: arr[] = {5, 6, 7, 8} Output: res[] = ... Read More