某方法{  
calculatedValue = addValues(leftHandSide, rightHandSide);
showResult(calculatedValue);//调用
}

private void showResult(int answer) => result.Text = answer.ToString();//被调用
//意思为answer 作为参数引入右边计算，再将右值return。
//约等于
private void showResult(int answer)
{
result.Text = answer.ToString();
return result.Text ;
}