3_Computer Science Grade 10 String_manipulation didactic material 2 2variant

Practical work

1)      Remove all characters except alphabets

This program takes a string (object) input from the user and removes all characters except alphabets.

#include <iostream>

using namespace std;

int main() {

    string line;

    cout << "Enter a string: ";

    getline(cin, line);

    for(int i = 0; i < line.size(); ++i)

    {

        if (!((line[i] >= 'a' && line[i]<='z') || (line[i] >= 'A' && line[i]<='Z')))

        {

            line[i] = '\0';

        }

    }

    cout << "Output String: " << line;   

    return 0;

}

Output

Enter a string: p2'r"o@gram84iz./

Output String: programiz

2)       Remove all characters except alphabets

This program below takes a string (C-style string) input from the user and removes all characters except alphabets.

#include <iostream>

using namespace std;

int main() {

    char line[100], alphabetString[100];

    int j = 0;

    cout << "Enter a string: ";

    cin.getline(line, 100);

    for(int i = 0; line[i] != '\0'; ++i)

    {

        if ((line[i] >= 'a' && line[i]<='z') || (line[i] >= 'A' && line[i]<='Z'))

        {

            alphabetString[j++] = line[i];

        }

    }

    alphabetString[j] = '\0';

    cout << "Output String: " << alphabetString;   

    return 0;

}

Output

Enter a string: P2'r"o@gram84iz./

Output String: Programiz

3)      You will learn to compute the length (size) of a string (both string objects and C-style strings).

Example: Length of String Object

#include <iostream>

using namespace std;

int main()

{

    string str = "C++ Programming";

    // you can also use str.length()

    cout << "String Length = " << str.size();

    return 0;

}

Output

String Length = 15

Example: Length of C-style string

To get the length of a C-string string, strlen() function is used.

#include <iostream>

#include <cstring>

using namespace std;

int main()

{

    char str[] = "C++ Programming is awesome";

    // you can also use str.length()

    cout << "String Length = " << strlen(str);

    return 0;

}

Output

String Length = 26

In this example, frequency of occurrence of a character is checked for both (String object and C-style string).

Example 1: Find Frequency of Characters of a String Object

#include <iostream>

using namespace std;

int main()

{

    string str = "C++ Programming is awesome";

    char checkCharacter = 'a';

    int count = 0;

    for (int i = 0; i < str.size(); i++)

    {

        if (str[i] ==  checkCharacter)

        {

            ++ count;

        }

    }

    cout << "Number of " << checkCharacter << " = " << count;

    return 0;

}

Output

Number of a = 2

4)      Loop is iterated until the null character '\0' is encountered. Null character indicates the end of the string.

In each iteration, the occurrence of the character is checked.

Example 2: Find Frequency of Characters in a C-style String

#include <iostream>

using namespace std;

int main()

{

   char c[] = "C++ programming is not easy.", check = 'm';

   int count = 0;

   for(int i = 0; c[i] != '\0'; ++i)

   {

       if(check == c[i])

           ++count;

   }

   cout << "Frequency of " << check <<  " = " << count;

   return 0;

}

Output

Number of m = 2