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how to use switch statment

im new with JS and i read about the switch statement. i dont know how to use it
i got an exercise to complete.
got an array with numbers 1-10 and the result need to be with words like "one","two","three"..
Thats what i got so far :
function sayNum(){
let nameNumber = [1,2,3,4,5,6,7,8,9,10]
let text = '';
for(let i=0;i<nameNumber.length;i++){
switch(numbers) {
case "1":
text = "one";
break;
case "2":
text = "two";
break;
case "3":
text = "three";
break;
case "4":
text='four';
break;
case "5":
text = "five";
break;
case "6":
text = "six";
break;
case "7":
text = "seven";
break;
case "8":
text = "eight";
break;
case "9":
text = "nine";
break;
case "10":
text = "ten";
}
}
return text;
}
sayNum()

You could do it like this, for example:
function sayNum(){
let numbers = [1,2,3,4,5,6,7,8,9,10];
let result = [];
for(let i=0;i<numbers.length;i++) {
switch(numbers[i]) {
case 1:
text = "one";
break;
case 2:
text = "two";
break;
case 3:
text = "three";
break;
case 4:
text = "four";
break;
case 5:
text = "five";
break;
case 6:
text = "six";
break;
case 7:
text = "seven";
break;
case 8:
text = "eight";
break;
case 9:
text = "nine";
break;
case 10:
text = "ten";
break;
}
result.push(text);
}
return result;
}
let namedNumbers = sayNum();
console.info(namedNumbers);
This will:
Add the textual values to an array, representing each number in the source array
Return the resulting array to the caller
Log the result in the console

In the switch statement, you pass an 'expression' into the switch statement. The expression itself can be a string, a number, float, boolean etc. Now, the expression is compared to each of the case clause. And this is a 'strict' comparison. And that is the reason why your code was not working.
Firstly you were passing an undeclared variable, 'numbers' as the switch expression. Instead, you should be passing the ith element of the nameNumber[i] array like so: switch(nameNumber[i]){ }
And, secondly, in each of your case clauses, you are comparing the value to a string like "1", "2". But the switch expression is compared using strict equality === operator, therefore when your nameNumber array contains numbers and not strings, your 'case' clauses should also have numbers and not strings. That means case 1: instead of case "1":.
You can read more about the switch-case here: Switch Statement
I have fixed your code below with the changes I mentioned above. Please run the below code snippet to see how it works. Goodluck!
function sayNum(){
let nameNumber = [1,2,3,4,5,6,7,8,9,10]
let text = '';
for(let i=0;i<nameNumber.length;i++){
switch(nameNumber[i]) {
case 1:
text = "one";
break;
case 2:
text = "two";
break;
case 3:
text = "three";
break;
case 4:
text='four';
break;
case 5:
text = "five";
break;
case 6:
text = "six";
break;
case 7:
text = "seven";
break;
case 8:
text = "eight";
break;
case 9:
text = "nine";
break;
case 10:
text = "ten";
}
console.log(text);
}
return text;
}
sayNum();

Rather than using a switch, use if statement. Because in switch, break statement can be used to jump out of a loop.
let text = '';
function sayNum() {
let nameNumber = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
for (let i = 0; i < nameNumber.length; i++) {
if(nameNumber[i] == 1){
text += `"one",`;
}
if(nameNumber[i] == 2){
text += `"two",`;
}
if(nameNumber[i] == 3){
text += `"three",`;
}
if(nameNumber[i] == 4){
text += `"four",`;
}
if(nameNumber[i] == 5){
text += `"five",`;
}
if(nameNumber[i] == 6){
text += `"six",`;
}
if(nameNumber[i] == 7){
text += `"seven",`;
}
if(nameNumber[i] == 8){
text += `"eight",`;
}
if(nameNumber[i] == 9){
text += `"nine",`;
}
if(nameNumber[i] == 10){
text += `"ten"`;
}
}
}
sayNum();
console.log(text)

How do i make switch and if statement in one function

function texas(val) {
var answer = "";
switch(val) {
case 1:
case 2:
case 3:
var answer = "low";
case 4:
case 5:
case 6:
var answer = "medium";
break;
} else if(val => 7) {
var answer = "Huge"
}
return answer;
}
it says error Declaration or statement expected. ts(1128) [13, 7]
and it poits at the else if statement

You can use the "default" keyword, but you should probably update your code in order to handle the cases in which the value of the parameter is not positive or not a number:
function texas(val) {
if (val <= 0 || isNan(val)) {
throw new InvalidOperationException("val should be a positive number");
}
switch(val) {
case 1:
case 2:
case 3:
return "low";
case 4:
case 5:
case 6:
return "medium";
default:
return "Huge"
}
}

It's >= and the elsehas to be deleted. The varfor answer is unnecesary, just declare it once with let. You forgot the break in case 3:.
function texas(val) {
let answer = "";
switch(val) {
case 1:
case 2:
case 3:
answer = "low";
break;
case 4:
case 5:
case 6:
answer = "medium";
break;
}
if(val >= 7) {
answer = "Huge"
}
return answer;
}
console.log(texas(2));
console.log(texas(8));

You just need to return in the switch
function texas(val) {
var answer = "";
switch(val) {
case 1:
case 2:
case 3:
var answer = "low";
return answer;
case 4:
case 5:
case 6:
var answer = "medium";
return answer;
}
if(val => 7) {
var answer = "Huge"
}
return answer;
}

The syntax does not allow to put an else after a switch. else only makes sense in combination with an if statemen. But switch has a default: case which most closely matches your intention (hopefully):
function texas(val) {
var answer = "";
switch(val) {
case 1:
case 2:
case 3:
var answer = "low";
break;
case 4:
case 5:
case 6:
answer = "medium";
break;
default:
if(val >= 7) {
answer = "Huge"
}
// decide what should happen if val is 0, -1 or not even a number (e.g. texas('gotcha!')
break;
}
return answer;
}
Don't forget to put break in your cases, otherwise execution will "fall through" and execute the next cases. You would never end up with "low"

You can't use an if statement within a switch block.
You do have the default option tho -
function texas(val) {
var answer = "";
switch(val) {
case 1:
case 2:
case 3:
answer = "low";
case 4:
case 5:
case 6:
answer = "medium";
break;
default:
answer = val >= 7 ? "Huge" : "Invalid";
break;
}
return answer;
Note that if you have a minus / negative answer, it'll also fall into this clause, but you can the the value of answer with an inline ?: if statement...

You can't put the else after the switch block as people have stated above. switch statement is better for multi way branching and fixed data values. On the other side, if statement is better for boolean values. You can do something like this. It might not be the shortest line of codes, but just so you that there's another approach:
function texas(val) {
let answer = "";
switch (true) {
case (val == 1 || val == 2 || val == 3):
answer = "low";
break;
case (val == 4 || val == 5 || val == 6):
answer = "medium";
break;
case (val >= 7):
answer = "huge";
break;
}
return answer;
}

Why can I not view an updated count for a variable with console.log in Javascript?

I currently have this code below, it is supposed to emulate a card counting system, in which different characters increment/decrement the count when passed. The code below runs successfully, but when I attempt console.log(cc(2,3,4,5,6); it returns 1 Bet, when I know the code runs 5 Bet, as those characters should increment the count, yet console.log does not return the accurate count, I assume this is due to scope? But I would like if someone could explain why count isn't accurately returned.
var count = 0;
function cc(card) {
switch(card) {
case 2:
case 3:
case 4:
case 5:
case 6:
count += 1;
break;
case 7:
case 8:
case 9:
count += 0;
break;
case 10:
case 'J':
case 'Q':
case 'K':
case 'A':
count -= 1;
break;
}
if (count > 0) {
return count + " Bet";
}
else {
return count + " Hold";
}
}
cc(2,3,4,5,6); \\ returns 5 Bet
console.log(cc(2,3,4,5,6)); \\ returns 2 Bet

var count = 0;
const bet = card => {
switch (card) {
case 2:
case 3:
case 4:
case 5:
case 6:
count += 1;
break;
case 7:
case 8:
case 9:
count += 0;
break;
case 10:
case "J":
case "Q":
case "K":
case "A":
count -= 1;
break;
}
};
function cc(...moves) {
moves.forEach(bet);
if (count > 0) {
return count + " Bet";
} else {
return count + " Hold";
}
}
console.log(cc(2, 3, 4, 5, 6)); // returns 5 Bet
console.log(cc(2, 3, 4, 5, 6)); // returns 10 Bet

Use arguments or splat operator to get all arguments passed and then loop it:
function cc(...cards) {
var count = 0;
var card;
for (var i = 0; i < cards.length; i++) {
card = cards[i];
switch (card) {
case 2:
case 3:
case 4:
case 5:
case 6:
count += 1;
break;
case 7:
case 8:
case 9:
count += 0;
break;
case 10:
case 'J':
case 'Q':
case 'K':
case 'A':
count -= 1;
break;
}
}
if (count > 0) {
return count + " Bet";
} else {
return count + " Hold";
}
}
cc(2, 3, 4, 5, 6); // returns 5 Bet
console.log(cc(2, 3, 4, 5, 6)); // returns 2 Bet

You have two major problems.
First, your count need to start at zero every time you call cc(). Because you have declared count outside the function, its values is preserved between calls to cc(). By declaring it inside the function, it's initialized to zero before it starts counting the card values.
(Unless you want to continue to the previous count, in which case you should keep it declared outside the function)
Second, your function only accepts one argument. You need to make it accept a list of arguments. This can be done simply with the spread operator .... Then you need to loop through each card value and do the count.
function cc(...cards) { // accept a list of card values as arguments.
let count = 0
for (const card of cards) { // loop through all card values.
switch (card) {
case 2:
case 3:
case 4:
case 5:
case 6:
count += 1
break
case 7:
case 8:
case 9:
count += 0
break
case 10:
case 'J':
case 'Q':
case 'K':
case 'A':
count -= 1
break
}
}
if (count > 0) {
return `${count} Bet`
}
return `${count} Hold`
}
cc(2, 3, 4, 5, 6) // returns 5 Bet
console.log(cc(2, 3, 4, 5, 6)) // returns 5 Bet
console.log(cc(2, 3, 4, 5, 6)) // returns 5 Bet

Given an integer in the range 10-40 javascript [duplicate]

This question already has answers here:
JavaScript numbers to Words
(28 answers)
Closed 5 years ago.
Problem: Given an integer in the range 10-40, which determines the number of training assignments on a certain topic. Output a string-description of the specified number of tasks, ensuring the correct agreement of the number with the words "study assignment", for example: 18 - "eighteen study assignments", 23 - "twenty-three study assignments", 31 - "thirty one study assignments".
i wrote something like,
var ten,
set,
unit;
switch(ten){
case 11:
return "eleven";
break;
case 12:
return "twelve";
break;
case 13:
return "thirteen";
break;
case 14:
return "fourteen";
break;
case 15:
return "fifteen";
break;
case 16:
return "sixteen";
break;
case 17:
return "seventeen";
break;
case 18:
return "eighteen";
break;
case 19:
return "nineteen";
break;
}
if (ten<9) {
return "Error number is less than 9";
}
switch(set){
case 10:
return "ten";
break;
case 20:
return "twenty";
break;
case 30:
return "thirty";
break;
case 40:
return "fourty";
break;
}
if(set<9) {
return "Error number is less than 9";
}
switch (unit)
{
case 1:
return "on1";
break;
case 2:
return "two";
break;
case 3:
return "three";
break;
case 4:
return "four";
break;
case 5:
return "five";
break;
case 6:
return "six";
break;
case 7:
return "seven";
break;
case 8:
return "eight";
break;
case 9:
return "nine";
break;
}
Any help will be appreciated!

If you have a limited range of numbers and want an easy solution without any libraries, you could try simple mapping:
var numbers = {
'10': 'ten',
'11': 'eleven',
'12': 'twelve',
'13': 'thirteen'
// ...
};
console.log(numbers['11']); // 'eleven'
Otherwise the the already mentioned JavaScript numbers to Words seems a good solution.

Javascript case statement in the switch Statement

I have a problem with the 'case' statement in the 'switch' statement in java script.
My question is how to write more than one number in the 'case' statement and save all the work on writing multiple of commands for each number , ill try to explain myself better. i want to write in the case statement the
number 10-14 (10,11,12,13,14).
how can i write it?
thanks for helping and sorry for my bad english.
name = prompt("What's your name?")
switch (name)
{
case "Ori":
document.write("<h1>" + "Hello there Ori" + "<br>")
break;
case "Daniel":
document.write("<h1>" + "Hi, Daniel." + "<br>")
break;
case "Noa":
document.write("<h1>" + "Noa!" + "<br>")
break;
case "Tal":
document.write("<h1>" + "Hey, Tal!" + "<br>")
break;
default:
document.write("<h1>" + name + "<br>")
}
age = prompt ("What's your age?")
switch (age)
{
case "10":
document.write("you are too little" + name)
break;
case "14":
document.write("So , you are in junior high school" + name)
break;
case "18":
document.write("You are a grown man" + name)
break;
default:
document.write("That's cool" + name)
break;
}

Check out this answer Switch on ranges of integers in JavaScript
In summary you can do this
var x = this.dealer;
switch (true) {
case (x < 5):
alert("less than five");
break;
case (x > 4 && x < 9):
alert("between 5 and 8");
break;
case (x > 8 && x < 12):
alert("between 9 and 11");
break;
default:
alert("none");
break;
}
but that sort of defeats the purpose of a switch statement, because you could just chain if-else statments. Or you can do this:
switch(this.dealer) {
case 1:
case 2:
case 3:
case 4:
// Do something.
break;
case 5:
case 6:
case 7:
case 8:
// Do something.
break;
default:
break;
}

use this, if you dont provide break then control will fall down, In this way you can match for group of numbers in switch.
case 10:
case 11:
case 12:
case 14:
case 15: document.write("i am less than or equal to 15");break;

Say you wanted to switch on a number 10-14 (10,11,12,13,14) you can chain the cases together:
switch(number) {
case 10:
case 11:
case 12:
case 13:
case 14:
alert("I'm between 10 and 14");
break;
default:
alert("I'm not between 10 and 14");
break;
}

You can simply omit the break; statement.
switch (2) {
case 1: case 2: case 3:
console.log('1 or 2 or 3');
break;
default:
console.log('others');
break;
}
I wanted to play with the concept a bit, I do not recommend this approach, however you could also rely on a function that will create a control flow function for you. This simply allows some syntaxic sugar.
var createCaseFlow = (function () {
var rangeRx = /^(\d)-(\d)$/;
function buildCases(item) {
var match = item.match(rangeRx),
n1, n2, cases;
if (match) {
n1 = parseInt(match[1], 10);
n2 = parseInt(match[2], 10);
cases = [];
for (; n1 <= n2; n1++) {
cases.push("case '" + n1 + "':");
}
return cases.join('');
}
return "case '" + item + "':";
}
return function (cases, defaultFn) {
var fnStrings = ['switch (value.toString()) { '],
k;
for (k in cases) {
if (cases.hasOwnProperty(k)) {
fnStrings.push(k.split(',').map(buildCases).join('') + "return this[0]['" + k + "'](); break;");
}
}
defaultFn && fnStrings.push('default: return this[1](); break;');
return new Function('value', fnStrings.join('') + '}').bind(arguments);
};
})();
var executeFlow = createCaseFlow({
'2-9': function () {
return '2 to 9';
},
'10,21,24': function () {
return '10,21,24';
}
},
function () {
return 'default case';
}
);
console.log(executeFlow(5)); //2 to 9
console.log(executeFlow(10)); //10,21,24
console.log(executeFlow(13)); //default case

You have already gotten a few answers on how to make this work. However, I want to point out a few more things. First off, personally, I wouldn't use a switch/case statement for this as there are so many similar cases – a classic if/elseif/else chain feels more appropriate here.
Depending on the use-case you could also extract a function and then use your switch/case (with more meaningful names and values, of course):
function getCategory (number) {
if(number > 20) {
return 3;
}
if(number > 15) {
return 2;
}
if(number > 8) {
return 1;
}
return 0;
}
switch( getCategory( someNumber ) ) {
case 0:
// someNumber is less than or equal to 8
break;
case 1:
// someNumber is any of 9, 10, 11, 12, 13, 14, 15
break;
// ...
}
If the intervals are equally spaced, you could also do something like this:
switch( Math.floor( someNumber / 5 ) ) {
case 0:
// someNumber is any one of 0, 1, 2, 3, 4
break;
case 1:
// someNumber is any one of 5, 6, 7, 8, 9
break;
// ...
}
Also, it should be noted that some people consider switch/case statements with fall-throughs (= leaving out the break; statement for come cases) bad practice, though others feel it's perfectly fine.