编辑代码

public class Sign{
    public static void main(String[] args) {
        Sign sign = new Sign("Everything on sale, please come in", 15);
        System.out.println(sign.getLines());
    }

    private String message;
    private int width;
 
    public Sign(String message, int width){
        this.message = message;
        this.width = width;
    }

    public int numberOfLines(){
        int lineNumber = 0;
        if(message.length() == 0){
            lineNumber = 0;
        } else {
            if(message.length() % width == 0){
                lineNumber = this.message.length / width;
            } else if(message.length() % width != 0){
                lineNumber = this.message.length / width + 1;
            }
        }
        return lineNumber;
    }

    public String getLines(){
        String returnLine = "";
        if(message.length() == 0){
            return null;
        }

        int numLines = numberOfLines();
        for(int i = 0; i < numLines - 1; i++){
            returnLine = message.substring(i * width, (i + 1) * width) + ";";
        }
        return returnLine;
    }

}