Strings

What is a String?

A string is a collection of characters, such as letters, numbers, and symbols, that are used to represent text. Strings are typically enclosed in quotation marks ("" or '') to indicate that they are not to be interpreted as program code, but rather as a sequence of characters.

Here are some examples of strings:

"Hello, world!" is a string that represents a greeting.
"12345" is a string that represents a sequence of digits.
"I love programming" is a string that represents a statement of affection for coding.

Reversing a String

Reversing a string means changing the order of the characters in a string so that the last character becomes the first, the second last character becomes the second, and so on. For example, if we have a string hello, reversing it would result in the string olleh.

Code :

#include <iostream>
using namespace std;

int main() {
    string name = "Road To Code";
    
    cout<<"Before Reverse : "<<name<<endl;
    
    int start = 0; 
    int end = 11;
    
    while(start<end)
    {
        int temp = name[start];
        name[start] = name[end];
        name[end] = temp;
        
        start++;
        end--;
    }
    
    cout<<"After Reverse : "<<name<<endl;
  
    return 0;
}

Output :

Before Reverse : Road To Code
After Reverse : edoC oT daoR

In the above program, A string variable named name is defined and initialized to "Road To Code". The program then prints the original string to the console using the cout statement.

Next, two integer variables start and end are defined and initialized to 0 and 11 respectively. These variables are used to keep track of the start and end positions of the string while reversing it.

After that, a while loop is used to iterate over the string until the start position is less than the end position. Inside the loop, the characters at the start and end positions are swapped using a temporary variable temp. Then, the start and end positions are incremented and decremented respectively to move towards the center of the string.

Finally, the program prints the reversed string to the console using the cout statement.

Program Output which shows the original string "Road To Code" and its reversed form "edoC oT daoR".

But In the above program we directly revered main string so If you do not want to reverse the main string directly, you can create a new strig and store the characters of name string to it. Here is an example program:

Code :

#include <iostream>
using namespace std;

int main() {
    string name = "Road To Code";
    
    cout<<"Before Reverse : "<<name<<endl;
    
    string originalString = "Road To Code";
    
    int start = 0; 
    int end = 11;
    
    while(start<end)
    {
        int temp = name[start];
        name[start] = name[end];
        name[end] = temp;
        
        start++;
        end--;
    }

    cout<<"After Reverse : "<<name<<endl;
    
    cout<<"original String : "<<originalString<<endl;
  
    return 0;
}

Output :

Before Reverse : Road To Code
After Reverse : edoC oT daoR
original String : Road To Code

Now in the above program we declares another string variable named originalString and initializes it with the same value as name. This is just to demonstrate that the original string is not modified. Means our original string are safely store in originalString variable.

String Length

String length is to the number of characters in a string. It's the count of individual characters present in a string, including spaces, numbers, symbols, and letters. For instance, if we have a string "Hello World!", its length would be 12 since there are 12 characters in the string, including space between "Hello" and "World".

Code :

#include <iostream>

using namespace std;

int main()
{
    string text = "Pinki";
    int i = 0;
    
    while(text[i]!='\0')
    {
        i++;
    }
    cout<<"Length :"<<i;
    
    return 0;
}

Output :

Length : 5

In the above program, a string variable named text is declared and initialized with the value "Pinki". Then, an integer variable i is initialized to 0.

The while loop checks each character in the string by accessing it with the help of index variable i and continues until it reaches the null character \0, which is used to indicate the end of the string. Inside the while loop, the index variable i is incremented by 1 for each character.

Finally, after the while loop, the value of the index variable i represents the length of the string text. This value is printed on the console using the cout statement and the message Length : is added before it.

The output of this program will be Length :5 as the length of the string Pinki is 5.

Code :

#include <iostream>

using namespace std;

int main()
{
  string text = "Pinki Hole";
  
  cout<<"Length: "<<text.length();
  
    return 0;
}

Output :

Length: 10 In the above Program, A string variable named text is declared and initialized with the value "Pinki Hole".

The length() method of the string class is used to find the length of the string text. This method returns the number of characters in the string, excluding the null character \0.

Finally, the length of the string text is printed on the console using the cout statement and the message Length: is added before it.

The output of this program will be Length: 10 as the length of the string Pinki Hole is 10,which includes the space character.

Code :

#include <iostream>

using namespace std;

int main()
{
 
 string text = "Pinki Hole";
 int i;
 
 for(i=0; i>-1; i++)
 {
     if(text[i]=='\0')
     {
         break;
     }
 }
 
 cout<<"Length : "<<i;
    return 0;
}

Output :

Length : 10

String Palindrom

A string palindrome refers to a sequence of characters that reads the same way from both ends. In simple words, a string is said to be a palindrome if it remains the same even if its characters are read from left to right or right to left. For example, the strings racecar and level are palindromes because they read the same way from both directions.

Code :

#include <iostream>

using namespace std;

int main()
{
 string text;
 cout<<"Enter String: ";
 cin>>text;
 
 int length = text.length();
 
 int start = 0;
 int end = length-1;
 
 int flag = -1;
 
 while(start<end)
 {
     if(text[start]!=text[end])
     {
         flag = 0;
         cout<<"NOT Palindrome";
         break;
     }
     start++;
     end--;
 }
 if(flag==-1)
 {
     cout<<"Palindrome";
     
 }
    return 0;
}

Output :

Enter String:
madam
Palindrome

The above program checks whether a given string is a palindrome or not. The program prompts the user to input a string, then finds its length using the length() method of the string class.

Two integer variables start and end are initialized, where start represents the index of the first character of the string, and end represents the index of the last character of the string.

A flag variable flag is initialized to -1, which will be used to indicate whether the string is a palindrome or not. If the flag remains -1 after the execution of the program, it means that the string is a palindrome.

A while loop is used to check the characters of the string from both ends. The loop condition is while(start<end), which means that the loop continues until the start index is less than the end index.

Inside the while loop, an if statement checks whether the characters at the start and end indices of the string are equal or not. If they are not equal, it means that the string is not a palindrome. In this case, the flag is set to 0 and the message NOT Palindrome is printed on the console using the cout statement. The loop is then terminated using the break statement.

If the flag remains -1 after the while loop, it means that the string is a palindrome. In this case, the message Palindrome is printed on the console using the cout statement.

The output of this program will be Palindrome if the input string is a palindrome, and NOT Palindrome if it is not a palindrome.

ASCII

ASCII stands for American Standard Code for Information Interchange. It is a character encoding system that assigns numerical values to letters, digits, punctuation marks, and other symbols commonly used in the English language. ASCII has been used in various applications, such as text communication, data storage, and computer programming.

Character to ASCII Value

Code :

#include<iostream>
using namespace std;

int main()
{
    char alpha = 'A';
    cout<<(int)alpha;
    
    return 0;
}

Output :

In the above program that declares a character variable named alpha and assigns the value A to it. Then, the program uses the cout statement to output the integer representation of alpha by Type casting it to an integer using the (int) operator.

In ASCII encoding, the character A has an integer value of 65. Therefore, this program would output 65 to the console.

ASCII Value to Character

Code :

#include<iostream>
using namespace std;

int main()
{
    char val =  67;
    cout<<(char)val;
    
    return 0;
}

Output :

In the above program that declares a character variable named val and assigns the integer value 67 to it. Then, the program uses the cout statement to output the character representation of val by casting it to a character using the (char) operator.

In ASCII encoding, the integer value 67 represents the character C. Therefore, this program would output C to the console.

Capital to Small

Code :

#include<iostream>
using namespace std;

int main()
{
    char capital = 'B' ;
    char small = capital + 32 ;
    cout<<small;
    
    return 0;
}

Output :

In the above program that converts a given uppercase alphabet into its corresponding lowercase alphabet.

The program first declares a char variable capital and initializes it to the uppercase alphabet B. Then, it declares another char variable small and assigns it the value of capital + 32.

In ASCII, the decimal value of B is 66, and the decimal value of b is 98. The program adds 32 to the ASCII value of B (i.e., 66+32=98) to get the ASCII value of b. The resulting value is then stored in the variable small.

Finally, the program uses the cout statement to display the value of small, which is the lowercase alphabet b.

When you run this program, the output will be b displayed on the console.

Code :

#include<iostream>
using namespace std;

int main()
{
   string str = "INDIA";
   
   for(int i=0; i<str.length(); i++)
   {
      if(str[i]>='A' && str[i]<='Z')
      {
           str[i] = str[i] + 32;
      }
   }
   
   cout<<"Small Letter is : "<<str;
    
    return 0;
}

Output :

Small Letter is : india

In the above program that converts uppercase letters in a given string to lowercase letters using ASCII values.

A string variable str is declared and initialized with the value "INDIA".A for loop is used to iterate through each character of the string str.An if statement is used to check if the current character is an uppercase letter. This is done by checking if the ASCII value of the character lies between the ASCII values of A and Z. If the character is an uppercase letter, its ASCII value is increased by 32 to convert it to its corresponding lowercase letter. This is done using the expression str[i] = str[i] + 32. After the for loop completes, the converted string str is displayed on the screen using the cout statement.

Small to Capital

Code :

#include<iostream>
using namespace std;

int main()
{
    char small = 'd' ;
    char captial = small - 32 ;
    cout<<captial;
    
    return 0;
}

Output :

In the above program that converts a given lowercase alphabet into its corresponding uppercase alphabet.

The program first declares a char variable small and initializes it to the lowercase alphabet d. Then, it declares another char variable capital and assigns it the value of small - 32.

In ASCII, the decimal value of d is 100, and the decimal value of D is 68. The program subtracts 32 from the ASCII value of d (i.e., 100-32=68) to get the ASCII value of D'. The resulting value is then stored in the variable capital.

Finally, the program uses the cout statement to display the value of capital, which is the uppercase alphabet D.

When you run this program, the output will be D displayed on the console.

Largest word from String

The concept of finding the largest word from a string involves iterating through each character of the string, and keeping track of the current word and its length. If a space is encountered, it means the current word has ended, so we check if it is longer than the previous maximum word and update the maximum word and its length accordingly. Once we have iterated through the entire string, we have found the largest word in the string.

Code :

#include<iostream>
using namespace std;

int main()
{
    string str = "khul ja sim sim";
    
    string currWrod = "";
    int currLength = 0;
    
    string maxWord = "";
    int maxlength = 0;
    
    for (int i=0; i<str.length(); i++)
    {
        if(str[i]== ' ')
        {
            currWrod = "";
            currLength = 0;
        }
        else
        {
            currWrod = currWrod +str[i];
            currLength++;
        }
        
        if(currLength > maxlength)
        {
            maxlength = currLength;
            maxWord = currWrod; 
        }
    }
    
    cout<<"Max word is "<<
    maxWord<<" with length: "<<maxlength;
    
    return 0;
}

Output :

Max word is khul with length: 4

In the above code line no 6 we create string variable str with the value khul ja sim sim. This is the input string we want to find the largest word from.

Line 8 to 12, the code initializes four variables: currWord, currLength, maxWord, and maxlength. currWord and currLength keep track of the current word and its length as we iterate through the input string. maxWord and maxlength keep track of the largest word we have found so far and its length.

In line 14 to 32, code then enters a for loop that iterates through each character of the input string str. Inside the for loop, the code checks if the current character is a space or not. If it is a space, it means the current word has ended, so the code resets currWord and currLength to start tracking a new word.After updating currWord and currLength, the code checks if the current word is longer than the previous largest word (maxWord). If it is, then we update maxWord and maxlength to store the new largest word and its length. Once we have iterated through the entire input string, the largest word and its length are stored in maxWord and maxlength. Finally, the code prints the largest word and its length to the console.

So, the output of this code is: Max word is khul with length: 4 This means that the largest word in the input string khul ja sim sim is khul, which has a length of 4.

What is a String?​

Reversing a String​

String Length​

String Palindrom​

ASCII​

Character to ASCII Value​

ASCII Value to Character​

Capital to Small​

Small to Capital​

Largest word from String​

What is a String?

Reversing a String

String Length

String Palindrom

ASCII

Character to ASCII Value

ASCII Value to Character

Capital to Small

Small to Capital

Largest word from String