String
To use string first of all you have to add this header #include <string>
Declaring and Initializing a String
It is very easy to declare a string. You can create a string variable nammed as MyString by typing string MyString ;
You can declare several string togather in a line. You can also initialize a string using string MyString = "Hello World!" .
You can also do that later in your code.
You can take a string from the user using cin >> MySting ; which only takes the string up to a space
If you want to get a full line including spaces use this instead getline( cin , MyString ) ;
Basic Sting Operations
Lets say you have two strings string a = "Hello " , b = "World" ; You can add string b after string a using a = a + b
after this opatertion the value of a will be “Hello World”.
That is how you can concatenate two strings.
You can delete last charecter on a sting using MyString.pop_back()
As you know string is an array of charecters so you can access any index (0 to length-1) and change that in constant time. e.g: MyString[0] = 'h' ;
You can print a string using cout << MyString << endl ;
You can check the equality of two strings using strA == strB and inequality using strA != strB .
You can also check which string is lexicographically greater using strA > strB vice versa.
String Functions :
| Function | Work of the function |
|---|---|
| MyString.size() | Returns The size of the string |
| str1.swap(str2) | Swaps the value of str1 and str2 |
| MyString.insert(x,s) | Inserts s in the xth index of MyString |
| MySrting.find(s) | Returns initial index of first occurrence of the s in MyString else returns -1 |
| MySrting.rfind(s) | Returns initial index of last occurrence of the s in MyString else returns -1 |
| MyString.replace(i,j,s) | Replaces j characters from ith index of MyString with new string s |
| stoi(MyString) | Returns the integer converted form of MyString |
| MyString.substr(i,k) | Returns a substing of length k from ith index of MyString |
| MyString.erase(i) | Erases every element from ith index to the end of MyString |
| MyString.clear() | Erases every element in MyStirng |
| MyString.empty() | Returns True if MyString is empty else return false |