Java Program to Find the First Capital Letter/Small Letter/Vowel/Consonant/Number/Whitespace/Special Character in a Given String

This is the Java Program to Find the First Capital Letter/Small Letter/Vowel/Consonant/Number/White Space/Special Character in a Given String.

Problem Description

Given a string, find the first position of the capital letter, small letter, vowel, consonant, whitespace, and special character if present in the string.
Example:

String x = “Ac @”

Output =
Capital letter = 1
Small letter = 2
Vowel = 1
Consonant = 2
Whitespace = 3
Special Character = 4

Problem Solution

Iterate through the string and find the first positions.

Program/Source Code

Here is the source code of the Java Program to Find the First Capital Letter/Small Letter/Vowel/Consonant/Number/White Space/Special Character in a Given String. The program is successfully compiled and tested using IDE IntelliJ Idea in Windows 7. The program output is also shown below.

```
 
```

// Java Program to Find the First Capital Letter/Small Letter/Vowel

// Consonant/Number/White Space/Special Character in a Given String

```
 
```
```
import java.io.BufferedReader;
```
```
import java.io.InputStreamReader;
```
```
 
```
```
public class FirstIndexes {
```
```
    // Function to display the output
```

    static void firstIndexes(String str){

        boolean consonant,vowel,capital,small,special,number,space;

        consonant = vowel = capital = small = special = number = space =false;

```
        int i;
```
```
        char ch;
```
```
        int count = 0;
```
```
        for(i=0; i<str.length(); i++){
```
```
            if(count == 7)
```
```
                break;
```
```
            ch = str.charAt(i);
```
```
            if(!space && ch == ' '){
```

                System.out.println("The index of first whitespace is " + (i+1));

```
                space = true;
```
```
                count++;
```
```
            }
```

            else if(!number && Character.isDigit(ch)){

                System.out.println("The index of first number is " + (i+1));

```
                number = true;
```
```
                count++;
```
```
            }
```
```
            if(Character.isLetter(ch)){
```

                if(!small && Character.isLowerCase(ch)){

                    System.out.println("The index of first lowercase character is "

                                                                          + (i+1));

```
                    small = true;
```
```
                    count++;
```
```
                }
```

                else if(!capital && Character.isUpperCase(ch)){

                    System.out.println("The index of first uppercase character is "

                                                                          + (i+1));

```
                    capital = true;
```
```
                    count++;
```
```
                }
```

                if(!vowel || !consonant){

                    ch = Character.toLowerCase(ch);

                    if(ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o'

                                                           || ch == 'u'){

                        System.out.println("The index of first vowel is "

                                                                 + (i+1));

```
                        vowel = true;
```
```
                        count++;
```
```
                    }
```
```
                    else{
```

                        System.out.println("The index of first consonant is "

                                                                      + (i+1));

                        consonant = true;

```
                        count++;
```
```
                    }
```
```
                }
```
```
            }
```

            else if(!special && ch != ' '){

                System.out.println("The index of first special character is "

                                                                     + (i+1));

```
                special = true;
```
```
                count++;
```
```
            }
```
```
        }
```
```
    }
```
```
    // Function to read the string
```

    public static void main(String[] args) {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

```
        String str;
```

        System.out.println("Enter the string");

```
        try {
```
```
            str = br.readLine();
```
```
        } catch (Exception e) {
```

            System.out.println("An I/O error occurred");

```
            return;
```
```
        }
```

        System.out.println("The first indexes are");

```
        firstIndexes(str);
```
```
    }
```
```
}
```

Program Explanation

1. In function firstIndexes(), several boolean variables consonant,vowel,capital,small,special,number and space are created and initialized to false.
2. The loop for(i=0; i<str.length(); i++) is used to iterate through the string.
3. The condition if(count == 7) checks whether each type of character is found, if is true, break from the loop.
4. The condition if(!space && ch == ‘ ‘) checks if the given character is a whitespace and displays it, if it is.
5. Similarly, the other else-if conditions check for remaining types of characters and display them.

Time Complexity: O(n) where n is the length of the string.

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Runtime Test Cases

 
Case 1 (Simple Test Case):
 
Enter the string
Ac @
The first indexes are
The index of first uppercase character is 1
The index of first vowel is 1
The index of first lowercase character is 2
The index of first consonant is 2
The index of first whitespace is 3
The index of first special character is 4
 
Case 2 (Simple Test Case - another example):
 
Enter the string
@Timbuchalka
The first indexes are
The index of first special character is 1
The index of first uppercase character is 2
The index of first consonant is 2
The index of first lowercase character is 3
The index of first vowel is 3

Sanfoundry Global Education & Learning Series – Java Programs.

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