2018-08-20 day06-作业
2018-08-20 本文已影响0人
我是一只菜鳥
<script>
//1.判断一个数是奇数还是偶数
var num1 = 101;
if (num1 % 2){
console.log(num1 + '是奇数');
} else{
console.log(num1 + '是偶数');
}
//2.给一个年份，判断是否是闰年
var year = 200;
if ((!(year%4) && year%100) || !(year%400)){
console.log(year + '闰年');
}else{
console.log(year + '不是闰年');
}
//3.给一个数n，计算n的阶乘
function factorial(num3){
var sum3 = 1;
for (var i = 1; i <= num3; i++){
sum3 *= i;
}
return sum3;
}
var num3 = 5;
console.log(num3 + '的阶乘为：' + factorial(num3));
//4.打印99乘法表
var str1 = '';
for (var i = 1; i < 10; i++){
for (var j = 1; j <= i; j++){
str1 = str1 + (j + '*' + i + '=' + i*j + ' ');
if (i==j){
str1 += '\n';
}
// console.log('%d * %d = %d', j, i, i*j);
}
}
console.log(str1);
//5.计算1-1/2+1/3-1/4 … 1/100的和
function sum5(num5){
var num;
if (num5 == 0){
return 0;
}
if (num5 % 2){
num = 1/num5;
} else{
num = -1/num5;
}
return num + sum5(num5-1);
}
console.log(sum5(100));
//6.给一个n，求1!+2!+3!+4!+5!...+n!
function factorials(num6){
if (num6 == 0){
return 0;
}
var sum6 = 1;
for (var i = 1; i <= num6; i++){
sum6 *= i;
}
return sum6 + factorials(num6-1);
}
console.log(factorials(4));
//7.找到所有的水仙花数
for (var i = 100; i < 1000; i++){
var b = parseInt(i / 100);
var s = parseInt(i / 10) % 10;
var g = i % 10;
if (i == b*b*b + s*s*s + g*g*g){
console.log(i);
}
}
//8.输入三个数，找到其中最大的，用一句话写出来
var num1 = prompt('请输入第1个数');
var num2 = prompt('请输入第2个数');
var num3 = prompt('请输入第3个数');
console.log('最大的数为：%d', Math.max(num1, num2, num3));
//9.给一个数组，找到其中最大值和最小值
var arr1 = [66, 601, 55, 2, 46, 88];
var max1 = arr1[0];
var min1 = arr1[0];
for (var i in arr1){
if (max1 < arr1[i]){
max1 = arr1[i];
}
if (min1 > arr1[i]){
min1 = arr1[i];
}
}
console.log('数组中的最大值为:%d; 最小值为:%d', max1, min1);
arr1.sort(function (a, b){return a < b;});
console.log('数组中的最大值为:' + arr1[0]);
arr1.sort(function (a, b){return a > b;});
console.log('数组中的最小值为:' + arr1[0]);
//11.自己实现随机 a, b 之间的整型
function radom(n, m){
var num = Math.random();
return n + parseInt((m - n)*num);
}
console.log(radom(10, 20));
</script>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<!--10.用while打印十行十列表格，表格里面写1-100，并且隔行变色-->
<script>
var tab = document.createElement("table")
tab.style.width = "500px";
var tb = document.createElement("tbody");
tab.appendChild(tb);
for(var i = 1; i < 11; i++){
var row = tb.insertRow(tb.rows.length);
for(var j = 1; j < 11; j++){
var col = row.insertCell(row.cells.length);
col.style.width = "50px";
col.style.height = "30px";
count = (i-1)*10 + j;
col.innerHTML = count;
}
var r = parseInt(Math.random()*256);
var g = parseInt(Math.random()*256);
var b = parseInt(Math.random()*256);
row.style.backgroundColor = "rgb(" + r + "," + g + "," + b + ")";
}
document.body.appendChild(tab);
</script>
<!--<script>
document.write('<table>');
for(var i = 1; i <= 10; i++){
document.write('<tr>');
for(var j = 1; j <= 10; j++){
r = parseInt(Math.random()*256);
g = parseInt(Math.random()*256);
b = parseInt(Math.random()*256);
count = (i-1)*10 + j;
document.write('<td style="width:50px;height:20px;background-color:rgb( %d, %d , %d );">');
document.write(count);
document.write('</td>');
// td.style.backgroundColor = 'rgb(' + r + ',' + g + ',' + b + ')';
}
document.write('</tr>');
}
document.write('</table>');
</script>-->
</body>
</html>
