Question

我正在尝试使用for循环来获取提示，但是如何从循环中获得平均值？当它在一个带有propmt的var中循环时，它就像var student [0]，var student [1]等，它们是如何定义的，所以我可以对它们求平均值？

<html>

<head>
<title>
    for
</title>
</head>

<body>
<p>
    Average your marks:
    <button onclick="myFunction()">Start</button>
</p>

<script type="text/javascript">
    function myFunction() {
        var Avg = "";
        for (var i = 0; i < 5; i++) { // this part makes the prompt below repeat 5 times 
                                       // but how would i multiply them.
            var Student = prompt("Enter your mark.  ");

            Avg +=                     // no clue what to do here
        }
        window.alert(Avg);
    }
</script>

</body>

</html>

Answer 1

function myFunction() {
    var sum = 0; // should be initialized to 0 not ""
    for (var i = 0; i < 5; i++) {
        var mark = prompt("Enter your mark: ");
        sum += Number(mark); // sum the marks (convert mark to number because prompt return a string)
    }
    var avg = sum / 5; // the average is the sum divided by the number of marks which is 5
    alert("Your average is: " + avg);
}

Answer 2

您可以做的是使用从提示输入的内容增加Avg变量。然后通过将总数除以将显示的提示量来获得平均值。

var Avg = 0;
for (var i = 0; i < 5; i++) {
    var Student = prompt("Enter your mark.  ");
    Avg += Student;
}
window.alert(Avg/5);

Answer 3

这也会提示用户输入标记的学生号码，如果用户没有输入任何认为学生标记为零的内容：

<!DOCTYPE html>
<html>
<body>

<p>Click the button to enter the 5 student's marks</p>

<button onclick="myFunction()">Start</button>

<p id="Average"></p>

<script>
function myFunction() {
    var sum = 0;
    var students = 5;
    for (var i = 1; i <= students; i++) { 
      var mark = prompt("Please the mark for student " + i, 0);
      sum += Number(mark)
    }
    document.getElementById("Average").innerHTML =
        "The average mark was: " + (sum/students);
}
</script>
</body>
</html>

对于具有平均值的循环

3 个答案: