#include <iostream>
#include <regex>
#include <string> 
#include <cctype>

using namespace std;

int main()

{
    std::string type = "videomp4";
    type = type.substr(0, type.find("/"));
    std::cout << type << '\n';
    
    // std::string name = "some_text-index-index";
    // std::string pattern = "index";
    // std::string replacement = "1";
    // size_t pos = name.find(pattern); // Find the position of the pattern in the string
    // while (pos != std::string::npos) { // Check if the pattern exists in the string
    //     name.replace(pos, pattern.length(), replacement); // Replace the pattern with the replacement string
    //     pos = name.find(pattern, pos + replacement.length);
    // }
    // std::cout << name << std::endl; // Output the modified string
    
    std::string id = "videoQWE-index";
    std::string indexPattern = "index";
    size_t pos = id.find(indexPattern);
    uint32_t streamNumber = 5;
    std::string index = std::to_string(streamNumber);
    
    std::vector<char> vec;
    if (vec.size() != 0) {
     std::cout << "y" << std::endl;
    } else {
      std::cout << "n" << std::endl;
    }
    
    char s[32]; // max of 64 bit int is 20 char long
    sprintf(s, "%02llu", 1);
    std::cout << "%02llu ->" << s << std::endl;
    
    sprintf(s, "%05u", 1);
    std::cout << "%01llu ->" << s << std::endl;
    
    sprintf(s, "%02llu", 12);
    std::cout << "%02llu ->" << s << std::endl;
    
    sprintf(s, "%01llu", 12);
    std::cout << "%01llu ->" << s << std::endl;
    
    
    
    return 0;
}

 std::vector<std::string> split(const string& input, const string& regex) {
    // passing -1 as the submatch index parameter performs splitting
    std::regex re(regex);
    std::sregex_token_iterator
        first{input.begin(), input.end(), re, -1},
        last;
    return {first, last};
 }

C++ Online Compiler

Write, Run & Share C++ code online using OneCompiler's C++ online compiler for free. It's one of the robust, feature-rich online compilers for C++ language, running on the latest version 17. Getting started with the OneCompiler's C++ compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as C++ and start coding!

Read inputs from stdin

OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.

#include <iostream>
#include <string>
using namespace std;

int main() 
{
    string name;
    cout << "Enter name:";
    getline (cin, name);
    cout << "Hello " << name;
    return 0;
}

About C++

C++ is a widely used middle-level programming language.

  • Supports different platforms like Windows, various Linux flavours, MacOS etc
  • C++ supports OOPS concepts like Inheritance, Polymorphism, Encapsulation and Abstraction.
  • Case-sensitive
  • C++ is a compiler based language
  • C++ supports structured programming language
  • C++ provides alot of inbuilt functions and also supports dynamic memory allocation.
  • Like C, C++ also allows you to play with memory using Pointers.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition);

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}