5.4. Strings¶
Strings are sequential collections of zero or more characters such as letters, numbers
and other symbols. There are actually two types of strings in C++ . The C++ string or just string from the
<string> library is the more modern type, and it is very similar to the Python string class.
The old style C-string which is essentially
an array of char type. The char type itself is actually distinct from both types of strings.
char cppchar = 'a'; // char values use single quotes
string cppstring = "Hello World!"; // C++ strings use double quotes
char cstring[] = {"Hello World!"}; // C-string or char array uses double quotes
In older versions of C++, you must use a char array to work with filenames. In modern
C++ (from C++11 onward), however, you can use a C++ string for everything.
Since C++ strings are so much nicer and similar to Python strings, I would not recommend using C-strings.
Because strings are sequences, all of the typical sequence operations work as you would expect. In addition, the string library offers a huge number of methods, some of the most useful of which are shown in Table 4.
| Method Name | Use | Explanation |
|---|---|---|
[ ] |
astring[i] |
access value of character at index i |
= |
astring[i]=value |
change value of character at index i |
+ |
string1 + astring2 |
concatenate strings |
append |
astring.append(string) |
Append to string the end of the string |
push_back |
astring.push_back(char) |
Appends a character to the end of the string |
pop_back |
astring.pop_back() |
Deletes the last character from the end of the string |
insert |
astring.insert(i, string) |
Inserts a string at a specific index |
erase |
astring.erase(i, j) |
Erases an element from one index to another |
find |
astring.find(item) |
Returns the index of the first occurrence of item |
size |
astring.size() |
Returns the size of the string |
Check your understanding by completing the following question.
-
Drag each data type to its' corresponding C++ initialization syntax.
Feedback shows incorrect matches.
- char
- 'a'
- char array
- {'a'}
- string
- "a"