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Container for storing elements of type char
+ View version details

Key Facts

Gyroscopic Couple: The rate of change of angular momentum (\inline \tau) = \inline I\omega\Omega (In the limit).
  • \inline I = Moment of Inertia.
  • \inline \omega = Angular velocity
  • \inline \Omega = Angular velocity of precession.

Blaise Pascal (1623-1662) was a French mathematician, physicist, inventor, writer and Catholic philosopher.

Leonhard Euler (1707-1783) was a pioneering Swiss mathematician and physicist.


The std::string class template is defined in the standard header <string>, and in the nonstandard backward-compatibility header <string.h>.
namespace std {
            typedef basic_string<char> string;


The class template basic_string stores and manipulates sequences of type char. std::string is an STL container which is part of basic_string for storing elements of type char.

Member Functions

Operation Description
constructor Create or copy a string
destructor Destroys a string
=, assign() Assign a new value
swap() Swaps values between two strings
+=, append(), push_back() Append characters
insert() Inserts characters
erase() Deletes characters
resize() Changes the number of characters (deletes or appends characters at the end)
replace() Replaces characters
+ Concatenates strings
==, !=, <, <=, >, >=, compare() Compare strings
size(), length() Return the number of characters
max_size() Returns the maximum possible number of characters
empty() Returns if the string is empty
capacity() Returns the number of characters that can held without be reallocation
[], at() Access a character
>>, getline() Read the value from a stream
<< Writes the value to a stream
copy() Copies or writes the contents to a C-string
c_str() Returns the value as C-string
data() Returns the value as character array
substr() Returns a certain substring
get_allocator() Returns the allocator


Operation Description
begin(), cbegin() Returns an iterator to the beginning
end(), cend() Returns an iterator to the end
rbegin(), crbegin() Returns a reverse iterator to the beginning
rend(), crend() Returns a reverse iterator to the end


Operation Description
find() Find characters in the string
rfind() Find the last occurrence of a substring
find_first_of() Find first occurrence of characters
find_first_not_of Find first absence of characters
find_last_of Find last occurrence of characters
find_last_not_of Find last absence of characters

Numeric conversions

Operation Description
stoi(), stol(), stoll() Converts a string to an signed integer
stoul(), stoull() Converts a string to an unsigned integer
stof(), stod(), stold() Converts a string to an floating point value
to_string() Converts an integral or floating point value to string
to_wstring() Converts an integral or floating point value to wstring


Example - I/O string
This simple program shows how to read and how to print out a string.
#include <iostream>
#include <string>
using namespace std;
int main()
    // Enter text into a string
    string qWord;
    cout << "Enter a word: ";
    cin >> qWord;
    cout << "The word is: " << qWord << endl;
    return 0;

Enter a word: Hello!
The word is: Hello!