[FIXED] Use of string buffers/join

Issue

StringUtils.concat(String[] strings) should join character strings end to end. For example, from an array which contains "f", "o", "o", "bar" it should result "foobar". Input: strings always contains at least one element. Implement StringUtils.concat(String[] strings).

I'm new in Java I'm trying to solve string join method Can you please guide me what i'm doing wrong and how I can solve this problem?

    public class StringUtils {
    static String concat(String[] strings) {
       strings=strings.length;
       String res="";
       for(int i=0;i<strings.length;i++) {
           res=res+strings.length;                  
       }
       return res;
  

   }

        public static void main (String[] args) {
                /* concatenates the given array of strings*/
            String[] array = {"f","o","o","bar"};
            String result = StringUtils.concat(array);
    
       }
    }

Solution

Instead of adding the length of the array, you should add the strings of the array:

static String concat(String[] strings) {
    String res = "";
    for (int i = 0; i < strings.length; i++) {
        res += strings[i]; // Shorthand for res = res + strings[i]
    }
    return res;
}

There is a better way to iterate the array using the for-each loop:

static String concat(String[] strings) {
    String res = "";
    for (String str : strings) {
        res += str;
    }
    return res;
}

You can even use the Stream API

static String concat(String[] strings) {
    return Arrays.stream(strings).collect(Collectors.joining());
}

Answered By - Arvind Kumar Avinash
Answer Checked By - Mary Flores (JavaFixing Volunteer)