javascript grade calculator using arrays and functions clarification
Question
I am trying to write a program that will display the letter grade once user inputs a real or float number. Prompt question works but the function is not working. I tried debugging the code with no success.
Any help is welcomed. Thanks!
var nameData = ['A', 'B', 'C', 'D', 'E', 'F']; var nameDataLength = nameData.length; var avgGrade = 0; var gradeDate = prompt('Enter your grade to check your letter grade'); function getAvg(nameData, gradeData) { for (var i = 0; i < nameData.length; i++) { alert("Your grades are " + nameData[i] + " ," + gradeData[i]); if (gradeData[i] >= 90) { alert("Your grades are " + nameData[i] + "A"); } else if (gradeData[i] >= 80) { alert("Your grades are " + nameData[i] + "B"); } else if (gradeData[i] >= 70) { alert("Your grades are " + nameData[i] + "C"); } else if (gradeData[i] >= 60) { alert(" Your grades are " + nameData[i] + "D"); } else { alert("Your grades are " + nameData[i] + "F"); } } }3 answers
solution1
1 2017-09-30 16:56:09
You could consider to take a function for getting a grade out of a given percent value.
This function features an early return, because if a value is found the function could be terminated without testing other values.
This pattern prevents to use a continuing if ... else if ... else if ... pattern, because only false condition goes on with checking.
function getGrade(percent) { if (percent >= 90) { return 'A'; } if (percent >= 80) { return 'B'; } if (percent >= 70) { return 'C'; } if (percent >= 60) { return 'D'; } return 'F'; } console.log(getGrade(90)); // A console.log(getGrade(81)); // B console.log(getGrade(72)); // C console.log(getGrade(63)); // D console.log(getGrade(54)); // F
solution2
0 2017-09-30 16:56:51
You have several problems:
- typo:
nameDate->nameData - you never call your function
- your function does not do what you think it does
I will solve the first two so that you can see the third.
var nameData = ['A', 'B', 'C', 'D', 'E', 'F']; var nameDataLength = nameData.length; var avgGrade = 0; function getAvg(gradeData) { for (var i = 0; i < nameData.length; i++) { alert("Your grades are " + nameData[i] + " ," + gradeData[i]); if (gradeData[i] >= 90) { alert("Your grades are " + nameData[i] + "A"); } else if (gradeData[i] >= 80) { alert("Your grades are " + nameData[i] + "B"); } else if (gradeData[i] >= 70) { alert("Your grades are " + nameData[i] + "C"); } else if (gradeData[i] >= 60) { alert(" Your grades are " + nameData[i] + "D"); } else { alert("Your grades are " + nameData[i] + "F"); } } } var gradeData = prompt('Enter your grade to check your letter grade'); // you need to actually call the function. getAvg(gradeData);
solution3
0 ACCPTED 2017-09-30 17:09:13
Have a look on this:
<!DOCTYPE html>
<html>
<body>
<p>Click the button to demonstrate the prompt box.</p>
<button onclick="myFunction()">Try it</button>
<p id="demo"></p>
<script>
function myFunction() {
var gradeData = prompt('Enter your grade to check your letter grade');
var grade=getGrade(gradeData);
alert(grade);
}
function getGrade(gradeData) {
if (gradeData >= 90) {
return 'A';
}
if (gradeData >= 80) {
return 'B';
}
if (gradeData >= 70) {
return 'C';
}
if (gradeData >= 60) {
return 'D';
}
return 'F';
}
</script>
</body>
</html>
The other way you can modify your code like the following:
<!DOCTYPE html>
<html>
<body>
<p>Click the button to type in your Marks and get grades.</p>
<button onclick="gradeCalculator()">Click here</button>
<p id="demo"></p>
<script>
var nameData = ['A', 'B', 'C', 'D', 'F'];
function gradeCalculator() {
var gradeData = prompt('Enter your grade to check your letter grade');
getAvg(nameData,gradeData);
}
function getAvg(nameData, gradeData) {
if (gradeData>= 90) {
alert("Your grades are " + nameData[0]);
} else if (gradeData >= 80) {
alert("Your grades are " + nameData[1]);
} else if (gradeData >= 70) {
alert("Your grades are " + nameData[2]);
} else if (gradeData >= 60) {
alert(" Your grades are " + nameData[3]);
} else {
alert("Your grades are " + nameData[4]);
}
}
</script>
</body>
</html>
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