C Articles - Page 36 of 95

In this problem, we are given two strings a text and a pattern. Our task is to create a program for KMP algorithm for pattern search, it will find all the occurrences of pattern in text string.Here, we have to find all the occurrences of patterns in the text.Let’s take an example to understand the problem, Inputtext = “xyztrwqxyzfg” pattern = “xyz”OutputFound at index 0 Found at index 7Here, we will discuss the solution to the problem using KMP (Knuth Morris Pratt) pattern searching algorithm, it will use a preprocessing string of the pattern which will be used for matching ... Read More

In this problem, we are given two string one text of size n and other a pattern of size m. Our task is to create a program for Anagram substring search.Here, we have to find all the occurrence of pattern and all its permutations (anagrams) in the text.Let’s take an example to understand the problem, Inputtext = “xyztrwqyzxfg” pattern = “xyz”OutputFound at index 0 Found at index 7To solve this problem, we will have to use an algorithm similar to the Rabin Karp algorithm which is used to check for anagram occurrence by adding the ASCII values of all characters ... Read More

In this program, we are given a file name text.txt. Our task is to print a particular line from the file.For this there are multiple methods in bash script, they are awk, sed, head.Syntax$> awk ‘{if(NR==LINE_NUMBER) print $0}’ filename $> sed -n LINE_NUMBERp filename $head -n LineNumber filename | tail - n + LINE_NUMBERCode to print a specific line in bash programming from file text.txt.Using awk$> awk ‘{if(NR==5) print $0}’ text.txtUsing sed$>sed -n 5p text.txtUsing head$head -n 5 filename | tail - n + 5

In this problem, we have to write a program in c that will print a string ‘ABCD’ repeatedly without using loop, recursion and any control structure.So, we will have to call or run the same block of code infinite time but without using loop, recursion or control structure which are the most common methods to perform the task. For this, we will run the same program multiple times instead of looping. This will perform our task within the given constraints. The system() method can be employed inside the code that will call the program infinite times.We will pass the file ... Read More

In C language both scanf() and gets() functions are defined to get input from external source and pass to system as input. Now there is some characteristics difference between both the functions.Following are the important differences between scanf() and gets() in C −Sr. No.Keyscanf() functiongets() function1DefinitionThe scanf() function can read input from keyboard and stores them according to the given format specifier. It reads the input till encountering a whitespace, newline or EOF.On other hand gets() function is used to receive input from the keyboard till it encounters a newline or EOF. The whitespace is considered as a part of ... Read More

In competitive programming, the most important thing is an effective code. Optimized and faster code is important and can make a difference in the ranks of the programmer.To write an effective c/c++ code in competitive programming, here are some effective tools for writing c/c++ code efficiently, First, let’s recall some basic terms, Template is writing code that does not depend on a particular type.Macro is a named code fragment.Vectors are like automatically resizable dynamic arrays that update size with insertion and deletion of the element.Now, let’s see some basic updates in code that can make in increasing efficiency of code, ... Read More

A program that can interact with the operating system irrespective of the OS on which it runs.Most of the compilers of c/c++ have the power to define macros that detect OS.Some Macros of GCC compiler are −_WIN32: macros for 32 bit and 64-bit Windows OS._WIN64: macros for 64-bit Windows OS._UNIX: macros for UNIX OS._APPLE_: macros for macOS.Based on these macros defined, let’s create a program that will work irrespective of the OS −Example Live Demo#include using namespace std; int main() {    #ifdef _WIN32     system("dir");    #else     system("ls");    #endif     ... Read More

In this article we will be discussing the working, syntax and examples of std::mbrtowc() function in C++ STL.What is std::mbrtowc()?std::mbrtowc() function is an inbuilt function in C++ STL, which is defined in the header file. mbrtowc() means that it converts the narrow multibyte character string to wide character. This function is used to convert a narrow multibyte character to wide character representation.Syntaxsize_t mbrtowc( wchar_t* pwc, char* str, size_t n, mbstate_t* ps);ParametersThe function accepts following parameter(s) −pwc − This is the pointer to the location we want the output to be stored.str − Character string which is used as the ... Read More

In this article we will be discussing the working, syntax and examples of putwchar() function in C++ STL.What is putwchar()?putwchar() function is an inbuilt function in C++ STL, which is defined in the header file. putwchar() function is used to write the wide character on the standard output device. This function takes the wide character from the arguments and writes it on the stdout or standard output of the system.This function is a wide character version of putchar() which is defined in the header file.Syntaxputwchar( wchar_t widec );ParametersThe function accepts following parameter(s) −widec − The wide character which ... Read More

In this tutorial, we will be discussing a program to understand how to read the alternate nth byte and write it in another file.For this, we will be provided with two .txt files. Our task is to write the contents from one file to another file using Iseek() which is used to change the pointer of the file descriptor.Example#include #include #include #include void func(char arr[], int n){    int f_write = open("start.txt", O_RDONLY);    int f_read = open("end.txt", O_WRONLY);    int count = 0;    while (read(f_write, arr, 1)){       if (count < n) ... Read More