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    Beginner's Guide
    First Steps
    Input & Output
    Custom Types – Part 1
    Diagnostics
    Standard Library
    Containers & Views
    Standard Algorithms
    Utilities
    Code Organization
    Custom Types – Part 2
    Generic Programming
    Memory Management
    Software Design Basics

    Strings (Basics)Strings (Basics)Strings

    std::string std::string

    • dynamic array of char (almost like vector<char>)
    • concatenation with + or +=
    • single character access with [index]
    • modifiable ("mutable") unlike in e.g., Python or Java
    • deeply copyable, deeply comparable
    #include <string>
std::string hw = "Hello";
std::string s = hw;     // copy of hw
hw += " World!";
cout << hw << '\n';     // Hello World!
cout << hw[4] << '\n';  // o
cout << s << '\n';      // Hello

    char = std::string's Element Type char char

    • one char can hold a single character
    • smallest integer type (usually 1 byte)
    • char literals must be enclosed in single quotes: 'a', 'b', 'c', …
    char c1 = 'A';   
char c2 = 65;  // ASCII code of 'A'
cout << c1 << '\n';          // A
cout << c2 << '\n';          // A
cout << (c1 == c2) << '\n';  // 1

    std::string s = "xyz"; 
s[1] = c1;
cout << s << '\n';           // xAz
s += c2;
cout << s << '\n';           // xAzA
    Special Characters
    backslash \ acts as escape character
    \n new line "Line1\nLine1\nLine3"
    \t tab "Column1\tColumn1\tColumn3"
    \' single quote "he said \'quote\' to me"
    \" double quote "he said \"quote\" to me"
    \\ backslash itself "C:\\Users\\me\\hello.cpp"

    std::string Manipulation Manipulation

    Literals

    'a' char
    "C-string literal" char const[]
    "std string literal"s std::string C++14
    "xyz"   is a "C-string"
    auto a = "seven of";  // type of a is char const[]
auto b = a;           // b refers to same object as a// refers to same object

    a += " nine";            //  COMPILER ERROR: can't be modified
auto c = "al" + "cove";  //  COMPILER ERROR

    std::string s = a;    // a is copied into s
s += " nine";         //  (s is std::string)
    "xyz"s is a std::string C++14
    #include <string>
using namespace std::string_literals;

    auto s1 = "seven of"s;  // type of s1 is std::string
auto s2 = s1;           // s2 is a copy of s1

    s1 += " nine";          // 
cout << s1 << '\n';     // seven of nine
cout << s2 << '\n';     // seven of

    auto s3 = "uni"s + "matrix"s;  // 
cout << s3 << '\n';     // unimatrix
    String literals that are only separated by whitespace are joined:
    "first" "second" ⇒ "first second"
    std::string b = "This is one literal"
                "split into several"
                "source code lines!";
    Raw String Literals

    Advantage: special characters can be used without escaping

    R"(raw "C"-string c:\users\joe )" char const[]} C++11
    R"(raw "std"-string c:\users\moe )"s std::string C++14

    std::getline getline

    • read entire lines / chunks of text at once
    • target string can be re-used (saving memory)
    std::string s;
getline(std::cin, s);        // read entire line
getline(std::cin, s, '\t');  // read until next tab
getline(std::cin, s, 'a');   // read until next 'a'
    Memory
    Beginner's Guide / First Steps
    References

    Last updated: 2020-07-05