js beginner Classic title
1. According to a digital date, this date is determined, for example, the day of the year: 2016 and 02 and 11, the calculation result is 42
1 var y = 2016;//+prompt("请输入年份") ;
2 var m = 2;
3 var day = 11;
4 var aDays = 0;
5 switch (m) {
6 case 12:
7 aDays += 30;
8 case 11:
9 aDays += 31;
10 case 10:
11 aDays += 30;
12 case 9:
13 aDays += 31;
14 case 8:
15 aDays += 31;
16 case 7:
17 aDays += 30;
18 case 6:
19 aDays += 31;
20 case 5:
21 aDays += 30;
. 4 Case 22 is:
= + 31 is aDays 23 is;
24. 3 Case:
25 IF (! Y. 4 == 0 &&% Y = 0% 100% 400 || Y == 0) {// Analyzing February 29 days or 28 days;
26 is aDays = 29 +;
27} the else {
28 aDays + = 28;
29}
30 Case 2:
31 is 31 is aDays + =;
32. 1 Case:
33 is aDays + = Day;
34 is BREAK;
35 default:
36 the console.log ( "error month ")
37 [BREAK;
38 is
39}
40 the console.log (aDays);
2: obtaining 1/1 - 1/4 ... ..1 / 100 - 1/2 + 1/3
SUM = 0 var;
var A =. 1;
for (i = var. 1; i <= 100; i ++) {
IF (i% 2 == 0) {// if i is even, then use -
SUM = SUM - A / I;
} the else {
SUM = SUM + A / I; // otherwise adding
}
}
the console.log (SUM);
3. basketball fell from 5 meters high, bounce every time the height of the original 30%, after several bounce, basketball height less than 0.1 meters.
Var. 5 = H. 1;
2 = I var. 1;
. 3 the while (to true) {
. 4 H H * = 0.3;
. 5 IF (H <0.1) {
. 6 the console.log ( "bounced" + i + "views") ;
. 7 bREAK; // if i is less than 0.1, the interrupt cycle;
. 8}
. 9 i ++;
10}
4. Print the 1000--2000 all the leap years, and outputs (document.write) in the form of four per row number
N-var = 0. 1;
2 for (var I = 1000; I <= 2000; I ++) {
. 3 IF (I. 4 == 0 &&% I = 0% 100% 400 I == 0 ||!) {
. 4 Document .write (I + "& nbsp; & nbsp; & nbsp;");
. 5 n-++; // record the number of times, incrementing
6 if (n% 4 == 0 ) {// when a multiple of 4, the wrap;
. 7 document.write ( "<br>");
. 8}
. 9}
10}
5. Print right triangle
1 for(var j = 1; j <=6; j++){
2 for(var i = 1; i <= j; i++){
3 document.write("*");
4 }
5 document.write("<br>");
6 }
6. Print equilateral triangle
// split into three triangles, right triangle is reversed in a first, a second equilateral triangle, a triangle with a space to squeeze out.
1 for(var i=1; i <=7; i++){
2 for(var a = 7; a >i; a--){
3 document.write(" ");
4 }
5 for(var k = 1; k<i+3; k++){ //加三则按照3 5 7排列；不加则按照 2 4 6排列；
6 document.write("*");
7 }
8 for(var k = 1; k<i; k++){
9 document.write("*");
10 }
11 document.write("<br>");
12 }
7. Calculate the factorial // 10 * 1 * 2 * 3 * 4. . . * 10
1 var cj = 1;
2 for(var i = 1; i <= 10; i++){
3 //console.log(i);
4 cj = cj * i ;
5 }
6 console.log(cj);
8. daffodils number between 100-999 requirements // abc = a * a * a + b * b * b + c * c * c is the number of daffodils
For. 1 (I var = 100; I <= 999; I ++) {
2 the parseInt var A = (I / 100); // Get the hundreds digit
3 var b = parseInt (i / 10)% 10; // Get ten bits
4 var c = parseInt (i% 10); // Get a digit
. 5 IF (I == A * A * A + B * B * B + C * C * C) {
. 6 the console.log (I );
7}
8}
9. There is a board with 64 squares, sesame put a weight on the first box which is 0.00001kg, which put the second 2, the third inside with 4, put on the board all sesame by weight of a nested do loop;
//law:
//. 1. 1
2 *. 1 // 2
. 3. 1 * 2 * 2 //
. 4 //. 1 * 2 * 2 * 2
. 5 var SUM = 0;
. 6 for (var. 1 = K; K <= 64; K ++) {
NUM = var. 1. 7;
. 8 for (var. 1 = I; I <64; I ++) {
. 9 NUM = NUM * 2;; // accordance with the law, each multiplied by 2
10}
. 11 SUM = SUM + NUM; // every time the previous sum for adding;
12 is}
13 is the console.log (sum * 0.00001);
10. There is a small to large sorted array. Now enter a number, required by the laws of the original insert it into the array
/// The first, direct addition, for sorting Sort;
function INSERT (ARR, Data) {
arr.push (Data);
arr.sort (function (A, B) {
return A - B;
})
}
var arr = [3, 4, 5, 7, 8, 9];
console.log(insert(arr, data))
// 1 second
for (var I = 0; I <arr.length; I ++) {
2 IF (Data <ARR [I]) {
. 3 BREAK;
. 4}
. 5}
. 6 2. // this position to the end data, all again after a move
. 7 for (var J = arr.length -. 1; J> = I; J,) {
. 8 ARR [J +. 1] = ARR [J];
. 9}
10 // 3. the data to be inserted, at a position on the first step in finding
. 11 ARR [I] = data;
12 is}
13 is ARR = var [. 3,. 4,. 5,. 7,. 8,. 9];
14 the console.log (ARR );
15 INSERT (ARR,. 6);
16 the console.log (ARR);
A defined in claim 11. Each array 30, the array is a random number from 1 to 10, every 5 digits, the number average value of five
// define an array
var ARR = [];
for (var I = 0; I <30; I ++) {
arr.push (Random (1,10));
}
the console.log (ARR);
for (var L = 0; L <arr.length; + L =. 5) {
the console.log (arr.slice (L, L +. 5));
the console.log (AVG (arr.slice (L, L +. 5)));
}
/ / averaging
function AVG (myArr with) {
var SUM = 0;
for (var J = 0; J <myArr.length; J ++) {
SUM + = myArr with [J];
}
return SUM /myArr.length;
}
// generates a random number
function random (max, min) {
return Math.round (Math.random () * (max-min)) + min;
}
13. The write function generates 4 digital codes and generating 10 times, while the results into an array
function rnumber(){
var arr= [];
for(var i = 0; i<10; i++){
var a = random(0,9);
var b = random(0,9);
var c = random(0,9);
var d = random(0,9);
arr.push("" + a + b + c + d);
}
return arr;
}
console.log(rnumber());
//生成随机数
function random(max,min){
return Math.round(Math.random() * (max-min)) + min;
}
14. Sensitive word filtering // code problems! ! , Not yet resolved
var arr = ["a", "w", "e", "sv", "qw"];
var str = "aw暖哒e阿大阿sv,请问我去qw";
for (var i = 0; i < arr.length; i++) {
for (var j = 0; j < str.length; j++) {
str = str.replace(arr[i], "*");
}
}
console.log(str);
15. count the number of each character appearing showed {a: 2, b: 1, c: 2, d: 1}
STR = var "aabccdsdadadadsadadafqdqeqwsqwq";
// define an empty character
var newStr = "";
// Loop through STR
for (var I = 0; I <str.length; I ++) {
// If there is no null character str [i ], it will return -1,
IF (newStr.indexOf (STR [I]) == -1) {
// null character and placed in
newStr + STR = [I];
}
}
the console.log (newStr) ; // get the array to heavy characters
newobj = {} var;
for (var I = 0; I <str.length; I ++) {
IF (newobj [STR [I]]) {// first time is undefined, so take else, is 1 second and take the first one. If there newStr str [i], then ++, or
newobj [STR [I]] ++;
} the else {
newobj [STR [I]] =. 1;
}
}
the console.log (newobj);
16. The randomly generated within a five-digit number, and then outputs the total number of how many and what each is respectively
var fiveNumber = random(0, 99999);
var fiveString = fiveNumber.toString();
console.log("该数是" + fiveString);
console.log("该数共有" + (fiveString.length) + "位");
for (var i = 0; i < fiveString.length; i++) {
numI = parseInt(i);
console.log("第" + (numI + 1) + "位是" + fiveString.charAt(i));
// console.log(fiveString.charAt(i))
}
function random(max, min) {
return Math.round(Math.random() * (max - min)) + min;
}
