使用While和For循环查找上界之间的所有素数的程序

Program that uses While and For loops to find all Prime Numbers between an upper Bound

本文关键字:程序 之间 While For 循环 查找 使用      更新时间:2024-02-07

我在for循环中遇到了一些问题。while循环工作正常,但嵌套循环需要帮助。循环的概念对我来说是相当新的,我不太明白我在代码中做了什么。如有任何帮助,我们将不胜感激。

var number = parseInt(window.prompt("Enter number: ", ""));
var divisor;
var check;
var prime = true;
var num;
document.write("The factors of ", number, " are: </br>");
divisor = 1;
while (divisor <= number) {
    check = number % divisor;
    if (check == 0) {
        document.write(divisor, " ");
        if ((divisor != 1) && (divisor != number)) {
            prime = false;
        }
    }
    divisor = divisor + 1;
}
if (prime == true) {
    document.write("<br>The number is prime");
} else {
    document.write("<br> The number is composite");
}

让你兴奋的东西。这个程序使用for和while来检查素数。for循环用作if检查,但这将起作用。您还应该尝试使用函数来最小化代码。

var number = parseInt(window.prompt("Enter number: ", ""));
var result = isPrime(number);
function isPrime(number) {
    var start = 2;
    //USING WHILE
    while (start <= Math.sqrt(number)) {
       if (number % start++ < 1) return false;
    }
    return number > 1;
}
//USING FOR 
for (;result;){ 
   document.write("<br>The number is prime");
}
if(!result) {
   document.write("<br>The number is NOT prime");
}

作为一个新人,我想你可能需要在while循环中休息一下,因为你只需要检查一下它是否是素数。就像这样:

if((divisor != 1) && (divisor != number)){
prime= false;
break;
}