CC-16 : Count vowels in input String.

Description:

Given input String str, find and return the count of vowels in the String.

Test cases and expected outputs:

Input Parameters	Expected outputs
The input string is: asz-123.reader	Count of vowels: 4
The input string is: Buy123	Count of vowels: 1
The input string is: ABC	Count of vowels: 1

Pseudocode:

The java method should accept following input parameters: str (String).

Initialize char array chars=str.toCharArray().

Initialize int variable vCnt=0, we will use this variable to count number of vowels in str.

Iterate through chars using for loop using idx as loop variable, starting from index 0 and incrementing idx till we reach chars.length-1:

If chars[idx] is equal to any of the following a, e, i ,o, u, A, E, I, O, U then :

Increment vCnt by 1.

At the end of above loop, vCnt contains the sum of the vowels in str. Return vCnt.

Code:

public int stringCountVowels(String str) {
	char[] chars=str.toCharArray();
	int vCnt=0;
	for (int idx=0; idx < chars.length; idx++) {
		if (chars[idx]=='a'||chars[idx]=='e'||
				chars[idx]=='i'||chars[idx]=='o'||chars[idx]=='u'||
				chars[idx]=='A'||chars[idx]=='E'||
				chars[idx]=='I'||chars[idx]=='O'||chars[idx]=='U') {
				vCnt++;
		}
	}		
	return vCnt;		
}

	
public int stringCountVowelsWithAPI(String str) {
	int vCnt=0;
	String vowels="aeiouAEIOU";
	for (int idx=0; idx < str.length(); idx++) {
		if (vowels.contains(str.subSequence(idx, idx+1))) {
				vCnt++;
		}
	}		
	return vCnt;	
}

Click here to download and run code and test cases !

Below fully running code can be copied and run on Eclipse or other Java IDEs. Refer the classname in code below. If the class name below is "A", save the code below to a file named A.java before running it. Be sure to try your own test cases to enhance your understanding ! You can also tweak the code to optimize or add enhancements and custom features.

public class StringCountVowels {
	
public int stringCountVowels(String str) {
	char[] chars=str.toCharArray();
	int vCnt=0;
	for (int idx=0; idx < chars.length; idx++) {
		if (chars[idx]=='a'||chars[idx]=='e'||
				chars[idx]=='i'||chars[idx]=='o'||chars[idx]=='u'||
				chars[idx]=='A'||chars[idx]=='E'||
				chars[idx]=='I'||chars[idx]=='O'||chars[idx]=='U') {
				vCnt++;
		}
	}		
	return vCnt;		
}

	
public int stringCountVowelsWithAPI(String str) {
	int vCnt=0;
	String vowels="aeiouAEIOU";
	for (int idx=0; idx < str.length(); idx++) {
		if (vowels.contains(str.subSequence(idx, idx+1))) {
				vCnt++;
		}
	}		
	return vCnt;	
}

	
public static void main(String[] args) {
	StringCountVowels sp=new StringCountVowels();
	int retVal;
		
	try {
	String str1="Elephant";
	System.out.println("\n\nThe original string is: "+str1);
	retVal=sp.stringCountVowels(str1);
	if (retVal!=0) {
		System.out.println("Count of vowels: "+retVal);
	}else {
		System.out.println("There are *no* vowels in the String.");
	}
	retVal=sp.stringCountVowelsWithAPI(str1);
	if (retVal!=0) {
		System.out.println("Count of vowels: "+retVal);
	}else {
		System.out.println("There are *no* vowels in the String.");
	}
			
			
	str1="ABC";
	System.out.println("\n\nThe original string is: "+str1);
	retVal=sp.stringCountVowels(str1);
	if (retVal!=0) {
		System.out.println("Count of vowels: "+retVal);
	}else {
		System.out.println("There are *no* vowels in the String.");
	}
	retVal=sp.stringCountVowelsWithAPI(str1);
	if (retVal!=0) {
		System.out.println("Count of vowels: "+retVal);
	}else {
		System.out.println("There are *no* vowels in the String.");
	}
			
	str1="asz-123.reader";
	System.out.println("\n\nThe original string is: "+str1);
	retVal=sp.stringCountVowels(str1);
	if (retVal!=0) {
		System.out.println("Count of vowels: "+retVal);
	}else {
		System.out.println("There are *no* vowels in the String.");
	}
	retVal=sp.stringCountVowelsWithAPI(str1);
	if (retVal!=0) {
		System.out.println("Count of vowels: "+retVal);
	}else {
		System.out.println("There are *no* vowels in the String.");
	}
			
	str1="Buy123";
	System.out.println("\n\nThe original string is: "+str1);
	retVal=sp.stringCountVowels(str1);
	if (retVal!=0) {
		System.out.println("Count of vowels: "+retVal);
	}else {
		System.out.println("There are *no* vowels in the String.");
	}
	retVal=sp.stringCountVowelsWithAPI(str1);
	if (retVal!=0) {
		System.out.println("Count of vowels: "+retVal);
	}else {
		System.out.println("There are *no* vowels in the String.");
	}			
	}catch (Exception exception) {
	System.out.print("Exception,"+ exception);
	exception.printStackTrace();
				
	}
}

}