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. 

>⚠️ **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
>```

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

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

>⚠️ **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
>```

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

>⚠️ **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.

The Standard Library

Overview

Application of Libraries

Useful Functions

Adaptors for Functions

Pairs and Tuples

Reference Wrappers

Smart Pointers

Type Traits

Time Library

std::any, std::optional, and std::variant

Containers in General

Sequential Containers

Associative Containers in General

Ordered Associative Containers

Unordered Associative Containers

Adaptors for Containers

Iterators

Callable Units

Algorithms

Non-Modifying Algorithms

Modifying Algorithms

More Algorithms

New Algorithms with C++17

Numeric

Strings

String View

Regular Expressions

Input and Output Streams

Conclusion

Comparison and Concatenation

Comparison

String concatenation