Introduction

Suppose you need to process a set of characters in your program if you have no idea about strings. You would declare a variable for every character you want to process but with strings, this cumbersome process can be eased.

In a naive way, strings are a group of characters or a plain set of characters or simple text. These characters can vary from alphabets to numbers to symbols. 

In terms of C++, strings are a group of characters i.e. an array of characters terminated by ‘\0’.

Initialization of character arrays:

We can initialize character arrays in the following ways:

char str[4]=”TUF”;
char str[]={‘T’,’U’,’F’,’\0’};
char str[8]={‘s’,’t’,’r’,’i’,’v’,’e’,’r’,’\0’};

Let’s see a simple program to get a word from the user

Code:

#include<iostream>
using namespace std;
 
int main(){
    char str[50];
    cout<<"Enter a word ";
    cin>>str;
    cout<<"\n str holds: "<<str;
    return 0;
}

Creating string object:

We can also define strings by creating a string class object. Using string class gives flexibility in terms of size, unlike character arrays where the length of arrays needs to be pre-defined.

The string class also becomes useful in string manipulation.

We can declare a string using string class as follows

string str;
string s;

The following code is to read a string from the user.

Code:

#include<iostream>
#include<string>
using namespace std;
 
int main(){
    string s;
    cout<<"Enter a string: ";
    cin>>s;
    cout<<"\ns holds: "<<s;
 
    return 0;
}

String Functions

String class comes with a rich library of string functions which can come in handy in string manipulation and other processes.

We’ll see some of the string functions supported in C++

• string::length(): returns the length of the string

string s="takeuforward";
cout<<s.length(); // prints 12

• string::find(): returns the starting index of the character

string s="takeuforward";
cout<<s.find('a'); // prints 1

• string::substr(): accepts starting index as parameter and returns substring starting from that index to end.

string s="takeuforward";
cout<<s.substr(3); // prints euforward

• string::at(): accepts index as a parameter and returns character present at that index.

string s="takeuforward";
cout<<s.at(2); // prints k

• string::append(): accepts another string object, index, length, number of characters to copy as a parameter and pushes the defined parameter to the end of the string.

string s;
string str="takeuforward";
s.append(str);
cout<<s; // prints takeuforward

• string:: getline(): accepts istream object and string object as parameter and extracts characters from istream object and stores them into a string object until a delimiter character is found.

string s;
cout<<"Enter the string: ";
getline(cin,s);
cout<<"\ns holds: "<<s;

• string::compare(): accepts string object as a parameter and returns 0 or another integer if string matches or not respectively.

string s="takeuforward";
string str="striver";
s.compare(str) ? cout<<"doesn't match" : cout<<"matches";

• string::clear(): clears the string and makes it an empty string

string s="takeuforward";
s.clear();
cout<<s; // prints “”

• string::front(): can be used to access the first character of the string.

string s="takeuforward";
cout<<s.front(); // prints t

• string::back(): can be used to access the last character of the string.

string s="takeuforward";
cout<<s.back(); // prints d

String class vs character array

Now we try comparing string class and character array in C++.

Special thanks to Yash Mishra for contributing to this article on takeUforward. If you also wish to share your knowledge with the takeUforward fam, please check out this article