Reducing and printing a string Array-CodePudding

I am trying to reduce the string array by using a for a loop. This is an example I tried to do

User string input: Calculus
User input:5
output: CalcuCalcCalCaC

I have turned the string to a char array but the issue presents itself when trying to print them out multiple times. It only prints once and has the right starting output.

input string: Oregon
input number: 4

output: Oreg

I notice my for loop says that it is not looping when I hover over it on the IDE that I downloaded from JetBrains.

I tried different combinations of decrementing and incrementing but could not get that "for statement is not looping". Other than that I have tried different ways to do something in the for loop but I don't think anything needs to be done for now if the for loop is not looping then, right?

So my question is, how to reduce a string or char array and print the decrement value over and over again?

Here is my code so far for it.

public String wordDown(String userString, int userNum)
    {
        String stringModded = userString.substring(0, userNum);

        char[] charArray = stringModded.toCharArray();
        char repeat = ' ';

        for(int i = 0; i<userNum;   i)
        {
            repeat = (char) (repeat  charArray[i]);
            charArray[i] = repeat;

            for(int j = 1; i > charArray.length;   j)
            {
                String modWord = String.valueOf(charArray[i   1]);
                return modWord;
            }
        }

        return null;
    }

public static void main(String[] args)
    {
        int userNumber;
        String userString;

        RandomArrayFunctionalities ranMethod = new RandomArrayFunctionalities();

        Scanner in = new Scanner(System.in);

        System.out.println("\nEnter a word:");
        userString = in.next();

        System.out.println("\nEnter a number within the word scope that you just enter:");
        userNumber = in.nextInt();

        System.out.println(ranMethod.wordDown(userString, userNumber));

    }

CodePudding user response：

I think you are over complicating things, you don't need a char array at all and you only need a single loop, and a single return statement:

public String wordDown(String userString, int userNum) {
    String finalString = "";

    for (int i = 0; i < userNum;   i) {
        finalString = finalString   userString.substring(0, userNum - i);
    }

    return finalString;
}

Simply loop up to the inputted number and substring from 0 to inputtedNumber - loopCounter and append the result to the previously held String value.

Example Run:

Enter a word:
Calculus

Enter a number within the word scope that you just enter:
5
CalcuCalcCalCaC

Sidenote:

Technically you would want to use StringBuilder instead of appending String in a loop, but that is probably out of the scope of this question. Here is that version just for reference:

public String wordDown(String userString, int userNum) {
    StringBuilder sb = new StringBuilder();

    for (int i = 0; i < userNum;   i) {
        sb.append(userString.substring(0, userNum - i));
    }

    return sb.toString();
}

CodePudding user response：

You do not need to modify the original array. Use a StringBuilder to concatenate the successive parts of the word. Use the String.substring(int,int) method to pull out those parts. The example that follows uses a decrementing index to generate the successively smaller substrings.

public String wordDown(String word, int userNum) {
  StringBuilder sb = new StringBuilder();
  for (int length = userNum ; length > 0 ; --length) {
    sb.append(word.substring(0, length));
  }
  return sb.toString();
}