定义一个命名函数，并调用，显示当前是星期几。定义一个匿名函数，并调用，显示当前是星期几。

以下是 JavaScript 的代码示例：

命名函数示例：

function showDayOfWeek() {
  const daysOfWeek = ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];
  const today = new Date();
  const dayOfWeek = daysOfWeek[today.getDay()];
  console.log("Today is " + dayOfWeek);
}

showDayOfWeek(); // 调用函数

匿名函数示例：

const showDayOfWeek = function() {
  const daysOfWeek = ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];
  const today = new Date();
  const dayOfWeek = daysOfWeek[today.getDay()];
  console.log("Today is " + dayOfWeek);
};

showDayOfWeek(); // 调用函数

这两个函数的作用是相同的，都会输出当前是星期几。区别在于，命名函数需要给函数命名，而匿名函数则不需要，直接将函数赋值给一个变量即可。