Explore the full potential of C++ by mastering the standard library.

Become a C++ Programmer

The C++ standard library is a collection of all the tools and utilities available in C++. It received its latest update in 2017, known as C++17. The update introduces many new features that further optimize our code. This module will help us fully grasp C++ and use it to its full potential.

C++ Standard Library

# Comparison
Strings support the well-known comparison operators `==, !=, <, >, >=`. The comparison of two strings takes place on their elements. 

#include <iostream>
#include <string>
 
int main(){
 
  std::cout << std::boolalpha << std::endl;
 
  std::string first{"aaa"};
  std::string second{"aaaa"};
   
  std::cout << "first <  first :" << (first < first) << std::endl;
  std::cout << "first <=  first :" << (first <= first) << std::endl;
  std::cout << "first <  second :" << (first < second) << std::endl;
 
  std::cout << std::endl;
   
  std::string one{"1"};
  std::string oneOneOne= one+ std::string("1") +"1";
 
  std::cout << "1 + 1 + 1: " << oneOneOne << std::endl;
   
  std::cout << std::endl;
 
}

cpp17.tar.gz

C++17

C++20

# String concatenation
The + operator is overloaded for strings, so we can *add* strings. 

><span>⚠️</span> **The + operator is only overloaded for C++ strings**
>\
The C++ type system permits concatenation of C++ and C strings into C++ strings, but not concatenation of C++ and C strings into C strings. The reason is that the + operator is overloaded for C++ strings. Therefore only the second line is valid C++, because the C string is implicitly converted to a C++ string:
>```C++
>//...
>#include <string>
>//...
>std::string wrong= "1" + "1"; // ERROR
>std::string right= std::string("1") + "1"; // 11
>```

Can we merge and compare strings like we did with ranges? This lesson shows us how.

Comparison and Concatenation

Comparison