function helloWorld(){
console.log("Hello World!")
}
helloWorld();
output => Hello World!
function printName(name){
console.log("My Name is "+name);
}
printName("Alex");
output => My Name is Alex
In JavaScript, `prompt` is a built-in function that displays a dialog box with a message and an input field for the user to enter data. It's a way to interact with users and collect information from them in a simple text-based form. The `prompt` function takes two arguments:
-
Message (optional): A string that serves as the message or prompt displayed to the user. This message typically instructs the user on what kind of input is expected.
-
Default Value (optional): A string that is pre-filled in the input field as the default value. The user can either accept this value or provide a different one.
Here's the basic syntax for using the prompt function:
let userInput = prompt(message, defaultValue);The user's input, once entered, is returned as a string, or null if the user cancels the prompt. It's important to note that the prompt function can only capture simple text input and returns the result as a string, regardless of the actual data type of the input.
Example:
let no = prompt("Enter Number");
if (no !== null) {
alert("The number is , " + no + "!");
} else {
alert("You canceled the prompt.");
}In this example, the user is prompted to enter their name. If they enter a name and click "OK," their no is stored in the no variable, and an alert displays a greeting. If they click "Cancel," no will be null, and an alert indicates that the prompt was canceled.
It's important to handle the case where the user clicks "Cancel" to prevent unexpected behavior in your JavaScript code, as null is returned when the prompt is canceled.
function swapNumbers(a,b){
let temp = a;
a = b;
b = temp;
console.log(a,b);
}
-
the formula for converting the temp from faherehnhit to celcius is
-
temp in c = (F-32)*5/9
-
temp in f = (c * 9/5) + 32
function convertTempToCelcius(temp){ let result; result = ((temp - 32) * 5)/9; console.log(result);}
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function checkNumberEvenOrOdd(no){
if(no < 0)
console.log("Number is negative")
else if(no > 0)
console.log("number is positive")
else
console.log("number is zero");
}
function checkNumberEvenOrOdd(num){
if(isNaN(num) || num == 0)
console.log("Not a valid number")
else if(num %2 === 0)
console.log("number is even");
else if (num %2 !==0 )
console.log("number is odd");
}
- the function will check whether user inputs correct character from a-z or A-Z .
- after checking check whether the input character is either
a,e,i,o,uso it will vowel else constant. - we can ignore case like if user enters a or A it should be converted to lowerCase first and then check.
to check whether input character is character we can check the ascii code or unicode code (.charCodeAt())
function checkVowelOrConstant(char){
let charCode = char.toLowerCase().charCodeAt();
let vowels = ['a','e','i','o','u'];
if(charCode >=97 && charCode <=122){
if(vowels.includes(char.toLowerCase()))
console.log("vowel")
else
console.log("constant")
}else{
console.log("not a character");
}
}
-
to find largest among 3 numbers we have to compare 3 numbers with each other
-
consider 3 numbers to be 10,20,5
-
first 10 will be compared with 20 and 10 will be compared with 5, if is false we will move to second number comparison.
-
if not we will check for 20 with other 2 numbers, (20 > 10 && 20> 5) it is true means 20 is largest.
function LargestNumber(a,b,c){ if(a > b && a> c{ console.log("a is largest") } else if(b > a && b>c){ console.log("b is largest"); } else if(c > a && c > b){ console.log("c is largest"); } }
way : 1
function sumOfNaturalNumbers(n) {
let sum = 0;
for(let i=1;i<n;i++){
sum+=i;
}
console.log(sum);
}
way : 2
-
sum of n natural numbers can be calculated using n*(n+1)/2
function sumOfNaturalNumbers(n){ let result = (n*(n+1))/2; console.log(result);
}
-
String.fromCharCode(charCode). - returns the character at the paryicular code.
-
unicode charCode of A is 65 and a is 97
function printAlphabets(){ for(let i = 'A'.charCodeAt();i<='Z'.charCodeAt();i++){ console.log(String.fromCharCode(i)) } }
To check if a year is a leap year in JavaScript, you can use the following criteria: A leap year is either:
1. Divisible by 4, but not divisible by 100, or
2. Divisible by 400.
Here's a JavaScript function to check if a year is a leap year based on these criteria:
function isLeapYear(year) {
// Check if the year is divisible by 4 and not divisible by 100, or divisible by 400
return (year % 4 === 0 && year % 100 !== 0) || (year % 400 === 0);
}
// Example usage:
const yearToCheck = 2024;
if (isLeapYear(yearToCheck)) {
console.log(`${yearToCheck} is a leap year.`);
} else {
console.log(`${yearToCheck} is not a leap year.`);
}In this code:
- The
isLeapYearfunction takes ayearas input. - It checks two conditions:
- The year should be divisible by 4 and not divisible by 100 (
year % 4 === 0 && year % 100 !== 0). - Alternatively, the year can be divisible by 400 (
year % 400 === 0).
- The year should be divisible by 4 and not divisible by 100 (
- If either of these conditions is met, the function returns
true, indicating that the year is a leap year. Otherwise, it returnsfalse.
You can replace the yearToCheck variable with any year you want to check, and the function will determine if it's a leap year.
-
factorial of a number can be calculated by multiplying that number with the subequent descending number like
factorial of 5 can be calculated as 5 * 4 * 3 * 2 *1 = 120
how can we do this using code ?
-
we can subsequent multiply the number with its decrement value like.
function factorial(num){ let fact=1; // step 1 for(let i=num;i>0 ;i--){ fact*=i; } console.log("factorial of number is = ",fact) }
- step 1 : we took a variable fact and initailize it with default value 1.
- we iterate the number , but now we did the initialization with the num because we wanted the loop to start from number and should go till 1.
- fact = fact * i and after each statement i will be decrement by 1.
-
to make a calculator our function shpuld be able to perform all the mathemaical function.
function calculator(){ let no1 = +prompt("enter number 1"); let no2 = +prompt("enter number 2"); let operation = prompt("enter operation from (+,-,/,%,*)"); let result; switch(operation){ case '+': result = no1+no2; alert(result); break; case '-': result = no1-no2; alert(result); break; case '/': result = no1/no2; alert(result); break; case '*': result = no1*no2; alert(result); break; case '%': result = no1%no2; alert(result); break; }}
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