組み合わせの数の計算
int fact(int num){ int rs=1; for (int i=1;i<=num;i++){ rs = rs*i; } return rs; }
void permbutton_actionPerformed(ActionEvent e) { int rs=1; int nnum=Integer.parseInt(nField.getText()); int knum=Integer.parseInt(kField.getText()); rField.setText(Integer.toString(fact(nnum)/fact(nnum-knum))); }