Java中的方法帮助

以下是我的代码 . 当我试图调用正三角形或负三角形时，它会抛出错误 . 请帮忙！

下面是一些错误方法，类方法中的negativeTriangle不能应用于给定的类型; required：String，int，int found：无参数原因：实际和形式参数列表的长度不同

方法中的positiveTriangle方法不能应用于给定的类型; required：String，int found：无参数原因：实际和形式参数列表的长度不同

“）”预期“;”预计不会发表声明“;”预期找不到符号符号：变量字符串位置：类main

import java.util.Scanner;
public class main {


    public static void main(String[] args) {

        purpose();

        gettingPrintCharacter();

        gettingVarifyingInputs();

        positiveTriangle(String aChar, int amount));

        negativeTriangle(String aChar, int amount, int opposite);


    }

    public static void purpose() {  
        System.out.print("This program will print a right triangle. \nThe "
           + "character that is entered at the prompt will be used to print"
           + " a right triangle.  \nThe value that is entered at the prompt "
           + "will be the right triangle's height and width.  \nIf the value "
           + "is negative only an outline of the triangle will be printed "
           + "else a filled in triangle will be printed.\n\n");
        //displays purpose of program 
    }

    public static void gettingPrintCharacter(){
        Scanner keyboard = new Scanner (System.in);
        System.out.print("Enter the character to be used: ");
        String triangle = keyboard.next();
        //converts character(s) entered into string
        char aChar = triangle.charAt(0);
        //slects only the first character of the string
        //the string above is to "idiot" or accident prof if they enter 
        //more than one character
    }

    public static void gettingVarifyingInputs(){
        Scanner keyboard = new Scanner (System.in);
        int amount;
        boolean valid= false;
        while (!valid)//first loop unitl uers inputs correct value
        {// starts the main loop
            System.out.print("Enter a non-zero integer length (+/-1 through +/-16): ");
            amount = keyboard.nextInt();// length and width of triangle
            while(amount == 0 || amount >16 || amount <-16)// invalid input tester
            {// starts second loop for user to input correct value
                System.out.print("Input value outside of range");
                System.out.print("\nEnter a non-zero integer length (+/-1 through +/-16): ");
                amount = keyboard.nextInt();// length and width of triangle
            }// ends loop
            valid = true;// end user input loop
        }
    }

    public static void positiveTriangle(String aChar, int amount){

        int i = 1;
        int j = i;
        do { //first do loop
            do{//second do loop
                System.out.print(aChar);
                j++;
            }while (j<=i);//second while loop end
            System.out.println();
            i++;
            j=1;
        }while(i<=amount);//first while loop end
    }//ends last else 

    public static void negativeTriangle(String aChar, int amount, int opposite) {

        opposite = Math.abs(amount);//finds absolute value
        for (int i = 0; i <= opposite; i++) {// first negative loop
            for (int j = 0; j <= i; j++) { // second negative loop  
                if (i == opposite) { 
                    for (int k = 0; k<= opposite; k++)// third negative loop
                        System.out.print("*");//prints for right outside of triangle
                    break;//  ends third negative loop
                } 
                else if (i > 1) {
                    System.out.print("*");          
                    for (int k = 0; k < i - 1; k++)// fourth negative loop
                        System.out.print(" ");
                    System.out.print("*"); 
                    break;// end fouth negative loop                  
                } else //else to print outside of triangle
                    System.out.print("*");//prints for right outside of triangle
            } // restarts the negative  second loop
            System.out.println();
        }// restarts the negative first loop
    }// ends loop    
}