在程序中使用 charAt

Question

What I am trying to do is very elementary. The user should enter a name and the program prints only the initials of the name except for the last word.

Eg:

input - "Mansha Mannan UL Haque"
output - "M.M.U.Haque"

The program is as follows but it does not compile.

class joke
{
    public static void main(String str)
    {
        String alter=" "+str;
        int n=alter.length();
        for(int i=0;i<=n;i++)
        {
            char f=alter.charAt(i);
            if (f.compareTo(" ")>0)
            {
                System.out.println(alter.charAt(i+1));
            }
        }
    }
}

The error showed is char cannot be dereferenced.

Answer 1

Split your input string into string array then access each word and print its first char, for last word print it whole.

class joke
{
public static void main(String[] args)
{
    Scanner sc = new Scanner(System.in);
    String alter=sc.nextLine(); //take input from user
    String arr[] = alter.split(" ");
    int n=arr.length(); //total words in user string
    for(int i=0;i<n;i++)
    {

        if(i==n-1){   //if last word
             System.out.print(arr[i]);
        }
        else{
             System.out.print(arr[i].charAt(0)+". ");
        }
    }
}

}

Answer 2

This should do the trick

in this case name would be your input

  String name = "Mansha Mannan UL Haque";
    String[] nameArray = name.split(" ");
    String newName = "";
    for(int i = 0; i < nameArray.length; i++)
    {
        if(i != nameArray.length -1)
        {
            newName += nameArray[i].substring(0, 1) + ".";
        }
        else
        {
            newName += nameArray[i];
        }
    }

and you should also make your class joke public and change String str to String[] args