pascal.java

public class pascal {
    public static void main(String[] args) {
        try{
            pascalTriangle(5, 5);}
        catch(Exception e){System.out.println(e);}
    }

    public static int[] pascalTriangle(int n, int size)throws Exception{
        if(size<n){
            throw new IllegalArgumentException("Triangle size is smaller than rows ");
        }
        if(n == 0){
            int[] r = {1,0};
            printRow(r, n, size, 4);
            return r;
        }
        else {
            int[] r = pascalTriangle(n-1, size);
            int[] temp = new int[n+2];
            temp[0] = 1;
            for(int i= 0; i < r.length-1;i++){
               temp[i+1] = r[i] + r[i+1];
            }
            printRow(temp, n, size, 4);
            return temp;
        }
    }

    static void printRow(int[] row, int n, int size, int cellWidth) {
    // leading indent in cells
    System.out.print(" ".repeat((size - n) * (cellWidth / 2)));

    // print values
    for (int i = 0; i < row.length - 1; i++) {
        System.out.printf("%" + cellWidth + "d", row[i]);
    }
    System.out.println();
}
}