if 语句中的 Java 子字符串不起作用

Question

I'm trying to remove the last char in the string using substring method. Outside the if statement works normally. But inside it just goes through the if statement and returns original String .

public String getElkon(int p, int zbytek) {   
    System.out.println(zbytek);

    for (int i = 0; i < p; i++) {
        vysledek += elkon[i];
        vysledek += " ";
        System.out.println(vysledek);
    }
  ***if(zbytek != 0){
        vysledek = vysledek.substring(0, vysledek.length() - 1);
        return vysledek;
    }
    else{
        return vysledek;
    }***

}

Answer 1

Your code would be more straightforward if you didn't have to trim the trailing space from appending your String (s). Also, it isn't clear why you expect zbytek to control the trim . I think you wanted if (p != 0) (since that is your loop sentinel). I would use a StringJoiner to implement this like

public String getElkon(int p, int zbytek) {
    System.out.println(zbytek);
    StringJoiner sj = new StringJoiner(" ");
    for (int i = 0; i < p; i++) {
        sj.append(elkon[i]);
    }
    return sj.toString();
}

Answer 2

The last character in the string is a space, since you added it last time in the for loop.

To trim the last space before if statement you could use the code

public String getElkon(int p, int zbytek) {   
    System.out.println(zbytek);

    for (int i = 0; i < p; i++) {
        vysledek += elkon[i];
        vysledek += " ";
        System.out.println(vysledek);
    }

    if (p > 0)
        vysledek = vysledek.substring(0, vysledek.length() - 1);

    if(zbytek != 0){    
       ...
    }

    return vysledek;     
}