CODEWITHSUNDEEP
java
preeth
preeth

Reputation: 365

java program to return the sum of all integers found in the parameter String

i want write a java program to return the sum of all integers found in the parameter String. for example take a string like:" 12 hi when 8 and 9" now the answer is 12+8+9=29. but i really dont know even how to start can any one help in this!

Upvotes: 1

Views: 30680

Answers (9)

Kannan Ekanath
Kannan Ekanath

Reputation: 17601

I understand that this does not have the Java8 tag but I will put this out there in case someone finds it interesting 

String str = "12 hi when 8 and 9";
System.out.println(Arrays.stream(str.split(" "))
      .filter(s -> s.matches("[0-9]+")).mapToInt(Integer::parseInt).sum());

would nicely print out 29

Upvotes: 0

CK__
CK__

Reputation: 1311

You can have a look on the following code :-

public class Class02 
{
    public static void main(String[] args) 
    {
        String str = "12 hi when 8 and 9";
        int sum = 0;
        List<String> list = new ArrayList<String>();
        StringTokenizer st = new StringTokenizer(str.toLowerCase());
        while(st.hasMoreElements())
        {
            list.add(st.nextToken());
        }
        for(int i =0; i< list.size();i++)
        {
            char [] array = list.get(i).toCharArray();
            int num = array[0];
            if(!(num >= 'a' && num <= 'z'))
            {
                int number = Integer.valueOf((list.get(i).toString()));
                sum = sum + number;
            }
        }
        System.out.println(sum);
    }
}

Hope it will help you.

Upvotes: 0

java.mypassion
java.mypassion

Reputation: 95

 String s ="12 hi when 8 and 9";
     s=s.replaceAll("[^0-9]+", " ");

     String[] numbersArray= s.split(" ");
     Integer sum = 0;
     for(int i = 0 ; i<numbersArray.length;i++){
         if(numbersArray[i].trim().length() != 0){
             Integer value = Integer.valueOf(numbersArray[i].trim());
             sum = sum + value;

         }
     }

     System.out.println(sum);

Upvotes: 0

yellowB
yellowB

Reputation: 3020

Assume your words are separated by whitespace(s)：

Then split your input string into "tokens"(continuous characters without whitespace). And then loop them, try to convert each of them into integer, if exception thrown, means this token doesn't represents a integer.

Code:

public static int summary(String s) {
    String[] tokens = s.split("\\s+");
    int sum = 0;
    for(String token : tokens) {
        try {
            int val = Integer.parseInt(token);
            sum += val;
        }
        catch(NumberFormatException ne){
            // Do nothing
        }
    }
    return sum;
}

Upvotes: 0

Salix alba
Salix alba

Reputation: 7824

You could use a regular expression 

Pattern p = Pattern.compile("\\d+");
String s = " 12 hi when 8 and 9" ;
Matcher m = p.matcher(s);
int start = 0;
int sum=0;
while(m.find(start)) {
    String n = m.group();
    sum += Integer.parseInt(n);
    start = m.end();
}
System.out.println(sum);

This approach does not require the items to be separated by spaces so it would work with "12hiwhen8and9".

Upvotes: 0

Baby
Baby

Reputation: 5092

You may start with replacing all non-numbers from the string with space, and spilt it based on the space

String str = "12 hi when 8 and 9";
str=str.replaceAll("[\\D]+"," ");
String[] numbers=str.split(" ");
int sum = 0;
for(int i=0;i<numbers.length;i++){
    try{
        sum+=Integer.parseInt(numbers[i]);
    }
    catch( Exception e ) {
      //Just in case, the element in the array is not parse-able into Integer, Ignore it
    }
}
System.out.println("The sum is:"+sum);

Upvotes: 7

anand mahuli
anand mahuli

Reputation: 135

private static int getSumOfIntegersInString(String string) {
    /*Split the String*/
    String[] stringArray = string.split(" ");
    int sum=0;
    int temp=0;
    for(int i=0;i<stringArray.length;i++){
        try{
            /*Convert the numbers in string to int*/
            temp = Integer.parseInt(stringArray[i]);
            sum += temp;
        }catch(Exception e){
            /*ignore*/
        }
    }
    return sum;
}

Upvotes: 0

barak manos
barak manos

Reputation: 30136

Here is the general algorithm:

  1. Initialize your sum to zero.
  2. Split the string by spaces, and for each token:
    • Try to convert the token into an integer.
    • If no exception is thrown, then add the integer to your sum.

And here is a coding example:

int sumString(String input)
{
    int output = 0;
    for (String token : input.split(" "))
    {
        try
        {
            output += Integer.parseInt(token);
        }
        catch (Exception error)
        {
        }
    }
    return output;
}

Upvotes: 0

Sanjeev
Sanjeev

Reputation: 9946

You shall use Scanner to read your string

   Scanner s = new Scanner(your string);

And then read it using

  s.nextInt();

Then add these integers.

Upvotes: 0

Related Questions