Develop Reference

How to make element in Array change its' place

I'm beginner in JS. I've tried to understand Caesar Cipher ROT13, but it was too complicated for me. So I've tried to write my own code. Here it is below:
function encrip() {
var alphabet = ["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"];
var str = "Ni Hao";
var string = str.toUpperCase();
for (var i = 0; i < string.length; i++) {
for (var k = 0; k < alphabet.length; k++) {
if(string.charAt(i) == alphabet[k]) {
/* console.log(string.charAt(i) + ' ' + alphabet.indexOf(alphabet[k])); */
}
}
}
}
encrip();
But I am stuck. How to do:
1. Get value from var str and then access to var alphabet , after change each letter from var str value to next 3 from alphabet (var str each element's current position would be changed) For example: Input: Ni Hao ==> output: QL KDR
2. Create universal code, I mean, not only for changing position by 3, but when I give value '5', each element would be changed by next 5 positions from alphabet. So output can be changed when I change its' value
I hope I explained everything clearly. Thanks everyone in advance for help!!

you can use the following function to encrypt english words, the 1st parameter is the string to encrypt and the 2nd for shifting
function encryp(str,pos){
var alpha="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
var strUC=str.toUpperCase();
var enc="";
for(var i=0;i<strUC.length;i++){
if(strUC.charAt(i)!=" "){
enc+=alpha.charAt((alpha.indexOf(strUC.charAt(i))+pos)%26)
}
else{
enc+=" "
}
// in your case pos=3
}
return enc;
}
console.log(encryp("NiHao",3));

You don't need two for loops to do this. Iterate over the input string and find the index of each character in the alphabet array, if found add the shift to it to get the encrypted character.
To handle overflow use the modulus operator to cycle through the array.
Also I assume that you are not going use any special symbols to do the encryption.
function encrip(string, shift) {
var alphabet = ["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"];
string = string.toUpperCase();
let arr = [];
for (var i = 0; i < string.length; i++) {
let char = alphabet.indexOf(string[i]) !== -1 ? alphabet[(alphabet.indexOf(string[i]) %26) + shift] : " ";
arr.push(char);
}
let encryp = arr.join("");
console.log(encryp);
return encryp;
}
encrip("Ni Hao", 3);

First of all, instead of your inner for loop scanning the whole alphabet array, you can use the built-in function indexOf:
alphabet.indexOf('K') // returns 10
Secondly, you'll want to build up your enciphered string in a separate variable. For each letter, get the index of that letter in the alphabet, add your cipher offset parameter to that index and add the resulting letter from the alphabet to your new string. An important step is that when you add to the index of the letter, you want to make sure the resulting index is within range for the alphabet array. You can do that using the % (modulo) operator, which will wrap high values back round to the start of the array. In full:
function encipher(input, offset) {
var alphabet = ["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"];
var str = input.toUpperCase();
var result = '';
for (var i = 0; i < str.length; i++) {
letterIndex = alphabet.indexOf(str.charAt(i));
if (letterIndex === -1) {
result += str[i]; // if the letter isn't found in the alphabet, add it to the result unchanged
continue;
}
cipheredIndex = (letterIndex + offset) % alphabet.length; // wrap index to length of alphabet
result += alphabet[cipheredIndex];
}
console.log(result);
}
encipher('Ni Hao', 5); // output: 'SN MFT'

Printing in Javascript

i have a question that seems basic but i can't seem to figure it out.
Write a program that takes the value of a variable called “input” (declared as any whole number at the top of your program) and outputs a square made of asterisks () as large as the number (input). For example, if the “input” is declared with the value 5, your program would display a square made of 25 asterisks() – ie ; 5 asterisks () high, by 5 asterisks () long.
The code i've come up with so far is below. I don't really understand how to make a string continuously print. If i did star = i then it turns into numbers and will print the numbers. So how do i make it so they connect? I also can't figure out where i should put the new line. console.log(star "\n"); gives me an error. Please help :)
var input = 2;
var star = "*";
var i = 0;
do {
console.log(star);
i++;
} while (i < input);

You can use String.repeat() (ES6 only) along with \r\n to add new line
var input = 5,
star = "*",
str = [],
i = 0;
do {
str.push( Array(input).join(star) ); // use array(length).join
i++;
} while (i < input);
str = str.join("\r\n"); // add breaklines
console.log(str);

console.log Will output a single line to the console containing whatever you pass it as an argument. You are trying to print a line of n asterisks n times.
The first step you should take is constructing the string of asterisks. You can concatenate a string to another with the + operator:
var input = 2;
var star = "*";
var line = "";
for(var i = 0; i < input; i++) {
line = line + star;
}
Once you have constructed line you can then print it n times:
for(var i = 0; i < input; i++) {
console.log(line);
}

Hint: You could create an empty array and then create a loop ending at your wanted number of asterisks after which you will join all the members of the array together. (Writing the code here wouldn't help you much since you mentioned it's an homework).

You could approach this in two ways. If we call your input value n, then we can log either n strings each consisting of n stars, or we can log a single string, containing (n * n) stars, with line breaks after every nth star.
Below is an example of a function that could do this task.
function stars (input) {
var output = ''
for (var i = 0; i < input; i++) {
for (var j = 0; j < input; j++) {
output += '*'
}
output += '\n'
}
return output
}

You can use the repeat-function to print a character multiple times.
var input = 2;
var star = "*";
var i = 0;
while(i++ < input){
console.log(star.repeat(input));
}
This repeats the * character input times in input lines.

Javascript Random Name Guesser: Unresponsive Script Issues

This is my first post here and I am having trouble wording a question, so please bear with me as I have been on this issue for hours.
My friend and I have thought of a fun little function that is supposed to guess the user's name (through an <input> tag) in a certain amount of trials using the random number function to access string letters from an alphabet array numbered 0-25. The function is also supposed to give the user the number of trials it took to guess their name.
I keep getting a non-responsive script, (line 33 - The line containing the second "for loop").
var goal = document.getElementById("your_Name").value;
var alphabet = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"];
var goalArray = goal.split("");
var trials = 0;
var guessArray = new Array();
var i;
var n;
for (i = 0; i < goalArray.length; i++){
guessArray.push(alphabet[Math.floor(Math.random()*26)]);
}
while (goalArray != guessArray){
trials++;
guessArray = [];
for (n = 0; n < goalArray.length; n++){
guessArray.push(alphabet[Math.floor(Math.random()*26)]);
}
}
document.getElementById("appendomatic").innerHTML = "It took " + guessArray + " trials to guess correctly";
Any help or attempt to help would be immensely appreciated!
In case anyone was wondering: This little idea of ours was to test the randomness of Javascript's random function through trials (he made the same program in MatLab, so we are going to compare results of the random functions from both languages).

goalArray != guessArray is always true since they are two separate arrays; even if they contain the same elements.
Since they appear to just be arrays of individual letters in a-z you could compare them with something like goalArray + '' != guessArray, because the toString() of the arrays will compare correctly.

This is how I eventually got it to work (by nesting the while loop and second for loop in another for loop):
var goal = document.getElementById("your_Name").value;
var goalArray = goal.split("");
var alphabet = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"];
var trials = 0;
var guessArray = [];
for (i = 0; i < goalArray.length; i++){
guessArray.push(alphabet[Math.floor(Math.random()*26)]);
}
for (x = 0; x < goalArray.length; x++){
while (goalArray[x] != guessArray[x]){
trials++;
guessArray = [];
for (n = 0; n < goalArray.length; n++){
guessArray.push(alphabet[Math.floor(Math.random()*26)]);
}
}
document.getElementById("appendomatic").innerHTML = "It took " + trials + " trials to guess correctly";
}
}

Comparing 2 arrays to output total integer

I have 2 arrays of numbers. I want to go through each array and find the number of times 1 number from each array adds up to the particular amount x.
If the particular amount x is reached as many times as another set number n then the function should print 'YES'. If x does not reach the set number of n then the function should print 'NO'.
The values of x , n and both arrays are in a string input. These values have been split into arrays as seen below in the code.
I have set up 2 for loops to run through each array and an if statement that checks for the condition of x meeting n.
The arrays I'm using in this code should print out the result of 'YES' however every time I run the code I'm getting 'NO' ? I've tried tinkering with the code but nothing has worked.
Any idea on where this code is broke and how to fix the problem?
Thanks :)
code:
var input = '2\n3 10\n2 1 3\n7 8 9';
function processData(input) {
var inputArray = input.split('\n');
var n = inputArray[1][0];
var x = inputArray[1].split(' ')[1];
var arrayA = inputArray[2].split(' ');
var arrayB = inputArray[3].split(' ');
var total = 0;
for(var i = 0; i < arrayA.length; i++) {
for(var j = 0; j < arrayB.length; j++) {
if(arrayA[i] + arrayB[j] == x) {
total = total + 1;
} if (total == n) {
return 'YES';
}
}
}
return 'NO';
}
console.log(processData(input));

arrayA[i] and arrayB[j] are strings, so arrayA[i] + arrayB[j] will be the concatenation of them (ex: '2' + '3' === '23').
If your logic is correct (i didn't quite understand what you are trying to do), it should be enough to convert them to numbers before adding them, using parseInt or some other method:
if(+arrayA[i] + (+arrayB[j]) == +x) { // used unary + to convert to number
total = total + 1;
} if (total == n) {
return 'YES';
}
PS: A cleaner version would be to convert each string in the array to number, but that involves more than adding 3 characters to your code.
PS2: You have a weird way of getting the input data. If you get it from another place in your JS code, you could simply pass it as an object with the relevant structure, otherwise you could pass it around in a more ... common format, like JSON.

Generate Array Javascript

I want to generate an array in jQuery/JS, which contains "code"+[0-9] or [a-z].
So it will look like that.
code0, code1 ..., codeA, codeB
The only working way now is to write them manually and I am sure this is a dumb way and there is a way to generate this automatically.
If you give an answer with a reference to some article where I can learn how to do similar stuff, I would be grateful.
Thank you.

For a-z using the ASCII table and the JavaScript fromCharCode() function:
var a = [];
for(var i=97; i<=122; i++)
{
a.push("code" + String.fromCharCode(i));
}
For 0-9:
var a = [];
for(var i=0; i<=9; i++)
{
a.push("code" + i);
}

I'm using the unicode hexcode to loop through the whole symbols from 0-z:
var arr = [];
for (var i = 0x30; i < 0x7b;i++){
// skip non word characters
// without regex, faster, but not as elegant:
// if(i==0x3a){i=0x41}
// if(i==0x5b){i=0x61}
char = String.fromCharCode(i);
while(!/\w/.test(char)){char = String.fromCharCode(i++)};
// generate your code
var res = "code"+char;
// use your result
arr.push(res);
}
console.log(arr);
Here goes your example.
Docs:
Unicode Table
for loop
fromCharCode
JS Array and it's methods

you can generate array in javascript by using following code.
var arr = [];
for (var i = 0; i < 5; i++) {
arr.push("code"+ i);
}
please refer following links.
https://developer.mozilla.org/en/docs/JavaScript/Reference/Global_Objects/Array
http://www.scriptingmaster.com/javascript/JavaScript-arrays.asp

a = [];
for(i = 48; i < 91; i++) {
if (i==58) i = 65
a.push("code" + String.fromCharCode(i));
}
alert(a.join(',')) // or cou can print to console of browser: console.log(a);