1. 计算 2 的 N 次幂, n 可输入, n 为自然数
- var n = parseInt(Windows.prompt('input'));
- var mul = 1;
- for(var i = 0; i <n; i ++){
- mul *= 2;
- }
- document.write(mul);
2. 计算 n 的阶乘, n 可输入
- var n = parseInt(Windows.prompt('input'));
- var num = 1;
- for(var i = 1;i <= n; i ++){
- num *= i;
- }
- document.write(num);
3. 斐波那契数列, 1 1 3 5 8 , 输出第 n 项.
- var n = parseInt(Windows.prompt('input'));
- var first = 1,
- second = 1,
- third;
- if(n> 2){
- for(var i = 0; i <n - 2; i ++){
- third = first + second;
- first = second;
- second = third;
- }
- document.write(third);
- }else{
- document.write(1);
- }
4. 编写一个程序, 输入一个三位数的正整数, 输出是反向输出. 如果: 输入 456, 输出 654
- function reverse(){
- var num = Windows.prompt('input');
- var str = '';
- for(var i = num.length - 1; i>= 0; i --){
- str += num[i];
- }
- return str;
- }
- var number = reverse(123);
- console.log(number);
5. 输入 3 个数, 最后输出最大的那个数.
- var a = parseInt(Windows.prompt('input'));
- var b = parseInt(Windows.prompt('input'));
- var c = parseInt(Windows.prompt('input'));
- if(a> b){
- if(a> c){
- document.write(a);
- } else {
- document.write(c);
- }
- } else {
- if(b> c){
- document.write(b);
- }else {
- document.write(c);
- }
- }
6. 打印 100 以内的质数.
- var count = 0;
- for(var i = 0; i < 100; i ++){
- for(var j = 0; j <=i; j ++){
- if(i % j == 0){
- count ++;
- }
- }
- if(count == 2){
- document.write(i+ ' ');
- }
- count = 0;
- }
来源: http://www.qdfuns.com/article/51344/5534ed66c98813a4264bd2bb28727469.html