how to perform character concatenation in java

Question

String st="java is awesome";
   char[] ch=st.toCharArray();
    st="";
    for(int i=0;i<ch.length;i++)
    {
        if(ch[i]!='a')
            st=st+ch[i];
        else if(ch[i]=='a')
            st=st+ch[i]+'#';
    }
    System.out.println(st);

i have to perform character concatenation without using '+'.Is it possible?

[Why is "Is it possible to..." a poorly worded question?](https://softwareengineering.meta.stackexchange.com/questions/7273/why-is-is-it-possible-to-a-poorly-worded-question) — EJoshuaS - Stand with Ukraine, Mar 25 '17 at 19:36

score 1 · Answer 1 · answered Mar 25 '17 at 18:35

The best practice to deal with string concatenations is to use StringBuilder as shown below:

            String st="java is awesome";
            char[] ch=st.toCharArray();
            StringBuilder builder = new StringBuilder();
            for(int i=0;i<ch.length;i++) {
                if(ch[i] != 'a')
                    builder.append(ch[i]);
                else if(ch[i]=='a')
                    builder.append(ch[i]).append('#');
            }
            System.out.println(builder.toString());

without using any built-in methods – Neeraj Thakur Mar 27 '17 at 16:29 — Neeraj Thakur, Mar 27 '17 at 16:29

score 0 · Answer 2 · answered Mar 25 '17 at 20:14

You can use String.valueOf() and st.concat() method like this

    String st="java is awesome";
    char[] ch=st.toCharArray();
    st="";
    for(int i=0;i<ch.length;i++)
    {
        if(ch[i]!='a')
            st=st.concat(String.valueOf(ch[i]));
        else if(ch[i]=='a')
            st=st.concat(String.valueOf(ch[i])).concat(String.valueOf('#'));
    }
    System.out.println(st);

how to perform character concatenation in java

2 Answers2