Notice: This page requires JavaScript to function properly.
Please enable JavaScript in your browser settings or update your browser.Indexing a String | Text Data Type
C++ Data Types
course content

Зміст курсу

C++ Data Types

C++ Data Types

1. Introduction
OverviewArithmetic OperationsDivision int and doubleMath in C++Specifying a Type
2. Numerical Data Types
IntegersUsing IntegersType modifierFloatDoubleNumerical Data Types Summary
3. Text Data Type
CharStringIndexing a StringWorking With StringChanging The String PracticeFinding Text in a StringStrings in Memory
4. Other Data Types and Concepts
BooleanBoolean ExpressionsVoidAuto UnsignedImplicit Type ConversionExplicit Type Conversion

bookIndexing a String

We can access the elements of a string (which are chars) using indexing with square brackets [] just like we would do with an array. Using that, we can also replace a character at a given position.

With that indexing, you can try to access a wrong index (that is out of range), and the compiler will tell you nothing about that.

cpp

main

copy

              
1234567

            
#include <iostream>

int main()
{
    std::string word = "Codefinity";
    std::cout << word[12]; // Word's length is 10
}

As you can see, the output is weird, and C++ did not warn you about the problem (as always...). To avoid it, you can get the length of a string using the .length() method and ensure your index is smaller than the length of your string.

cpp

main

copy

              
123456789101112

            
#include <iostream>

int main()
{
    std::string word = "Codefinity";
    int index = 12;
    
    if (index >= word.length()) 
	    std::cout << "The output is unexpected!" << std::endl;
    else
        std::cout << word[index]; // Word's length is 10
}

Another way of indexing is using the .at() method. To get the character with index n, we can use the following syntax:

It works the same as str[n] but will raise an error if you specify an index that is out of range.

cpp

main

copy

              
123456789

            
#include <iostream>
using namespace std;

int main()
{
  string word = "Codefinity";
  cout << word.at(12); // word's length is 10
  return 0;
}

Try outputting the character with the index 5 in the code window above.

Let's sum up what we used in this chapter:

Practice

As was said before, we can replace the characters inside a string using indexing (both with [] and .at()). Here is an example:

cpp

main

copy

              
1234567891011

            
#include <iostream>
using namespace std;

int main()
{
  string word = "Cpdefinitu";
  word[1] = 'o';
  word.at(word.length()-1) = 'y'; // length-1 accesses the last element
  cout << word;
  return 0;
}

Завдання

Your task is to check if we can add characters to the end of a string that way.

  • Figure the index of the last character in a string.
  • Assign 'y' to the index index of last character + 1 of str.

Switch to desktopПерейдіть на комп'ютер для реальної практикиПродовжуйте з того місця, де ви зупинились, використовуючи один з наведених нижче варіантів
Все було зрозуміло?

Як ми можемо покращити це?

Дякуємо за ваш відгук!

Секція 3. Розділ 3
toggle bottom row

bookIndexing a String

We can access the elements of a string (which are chars) using indexing with square brackets [] just like we would do with an array. Using that, we can also replace a character at a given position.

With that indexing, you can try to access a wrong index (that is out of range), and the compiler will tell you nothing about that.

cpp

main

copy

              
1234567

            
#include <iostream>

int main()
{
    std::string word = "Codefinity";
    std::cout << word[12]; // Word's length is 10
}

As you can see, the output is weird, and C++ did not warn you about the problem (as always...). To avoid it, you can get the length of a string using the .length() method and ensure your index is smaller than the length of your string.

cpp

main

copy

              
123456789101112

            
#include <iostream>

int main()
{
    std::string word = "Codefinity";
    int index = 12;
    
    if (index >= word.length()) 
	    std::cout << "The output is unexpected!" << std::endl;
    else
        std::cout << word[index]; // Word's length is 10
}

Another way of indexing is using the .at() method. To get the character with index n, we can use the following syntax:

It works the same as str[n] but will raise an error if you specify an index that is out of range.

cpp

main

copy

              
123456789

            
#include <iostream>
using namespace std;

int main()
{
  string word = "Codefinity";
  cout << word.at(12); // word's length is 10
  return 0;
}

Try outputting the character with the index 5 in the code window above.

Let's sum up what we used in this chapter:

Practice

As was said before, we can replace the characters inside a string using indexing (both with [] and .at()). Here is an example:

cpp

main

copy

              
1234567891011

            
#include <iostream>
using namespace std;

int main()
{
  string word = "Cpdefinitu";
  word[1] = 'o';
  word.at(word.length()-1) = 'y'; // length-1 accesses the last element
  cout << word;
  return 0;
}

Завдання

Your task is to check if we can add characters to the end of a string that way.

  • Figure the index of the last character in a string.
  • Assign 'y' to the index index of last character + 1 of str.

Switch to desktopПерейдіть на комп'ютер для реальної практикиПродовжуйте з того місця, де ви зупинились, використовуючи один з наведених нижче варіантів
Все було зрозуміло?

Як ми можемо покращити це?

Дякуємо за ваш відгук!

Секція 3. Розділ 3
toggle bottom row

bookIndexing a String

We can access the elements of a string (which are chars) using indexing with square brackets [] just like we would do with an array. Using that, we can also replace a character at a given position.

With that indexing, you can try to access a wrong index (that is out of range), and the compiler will tell you nothing about that.

cpp

main

copy

              
1234567

            
#include <iostream>

int main()
{
    std::string word = "Codefinity";
    std::cout << word[12]; // Word's length is 10
}

As you can see, the output is weird, and C++ did not warn you about the problem (as always...). To avoid it, you can get the length of a string using the .length() method and ensure your index is smaller than the length of your string.

cpp

main

copy

              
123456789101112

            
#include <iostream>

int main()
{
    std::string word = "Codefinity";
    int index = 12;
    
    if (index >= word.length()) 
	    std::cout << "The output is unexpected!" << std::endl;
    else
        std::cout << word[index]; // Word's length is 10
}

Another way of indexing is using the .at() method. To get the character with index n, we can use the following syntax:

It works the same as str[n] but will raise an error if you specify an index that is out of range.

cpp

main

copy

              
123456789

            
#include <iostream>
using namespace std;

int main()
{
  string word = "Codefinity";
  cout << word.at(12); // word's length is 10
  return 0;
}

Try outputting the character with the index 5 in the code window above.

Let's sum up what we used in this chapter:

Practice

As was said before, we can replace the characters inside a string using indexing (both with [] and .at()). Here is an example:

cpp

main

copy

              
1234567891011

            
#include <iostream>
using namespace std;

int main()
{
  string word = "Cpdefinitu";
  word[1] = 'o';
  word.at(word.length()-1) = 'y'; // length-1 accesses the last element
  cout << word;
  return 0;
}

Завдання

Your task is to check if we can add characters to the end of a string that way.

  • Figure the index of the last character in a string.
  • Assign 'y' to the index index of last character + 1 of str.

Switch to desktopПерейдіть на комп'ютер для реальної практикиПродовжуйте з того місця, де ви зупинились, використовуючи один з наведених нижче варіантів
Все було зрозуміло?

Як ми можемо покращити це?

Дякуємо за ваш відгук!

We can access the elements of a string (which are chars) using indexing with square brackets [] just like we would do with an array. Using that, we can also replace a character at a given position.

With that indexing, you can try to access a wrong index (that is out of range), and the compiler will tell you nothing about that.

cpp

main

copy

              
1234567

            
#include <iostream>

int main()
{
    std::string word = "Codefinity";
    std::cout << word[12]; // Word's length is 10
}

As you can see, the output is weird, and C++ did not warn you about the problem (as always...). To avoid it, you can get the length of a string using the .length() method and ensure your index is smaller than the length of your string.

cpp

main

copy

              
123456789101112

            
#include <iostream>

int main()
{
    std::string word = "Codefinity";
    int index = 12;
    
    if (index >= word.length()) 
	    std::cout << "The output is unexpected!" << std::endl;
    else
        std::cout << word[index]; // Word's length is 10
}

Another way of indexing is using the .at() method. To get the character with index n, we can use the following syntax:

It works the same as str[n] but will raise an error if you specify an index that is out of range.

cpp

main

copy

              
123456789

            
#include <iostream>
using namespace std;

int main()
{
  string word = "Codefinity";
  cout << word.at(12); // word's length is 10
  return 0;
}

Try outputting the character with the index 5 in the code window above.

Let's sum up what we used in this chapter:

Practice

As was said before, we can replace the characters inside a string using indexing (both with [] and .at()). Here is an example:

cpp

main

copy

              
1234567891011

            
#include <iostream>
using namespace std;

int main()
{
  string word = "Cpdefinitu";
  word[1] = 'o';
  word.at(word.length()-1) = 'y'; // length-1 accesses the last element
  cout << word;
  return 0;
}

Завдання

Your task is to check if we can add characters to the end of a string that way.

  • Figure the index of the last character in a string.
  • Assign 'y' to the index index of last character + 1 of str.

Switch to desktopПерейдіть на комп'ютер для реальної практикиПродовжуйте з того місця, де ви зупинились, використовуючи один з наведених нижче варіантів
Секція 3. Розділ 3
Switch to desktopПерейдіть на комп'ютер для реальної практикиПродовжуйте з того місця, де ви зупинились, використовуючи один з наведених нижче варіантів
some-alt