Detailed explanation of loop usage in javascript examples

Detailed explanation of loop usage in javascript examples

I was bored and sorted out some simple exercises about loops. I hope it will be helpful to those who are just starting to learn JS.

1. Print the number and sum of all multiples of 7 between 1 and 100

var sum=0;
var n=0;
for(var i=1;i<=100;i++){
	if(i%7==0){
		sum+=i;
		++n;
		}
	}
console.log("The number is: "+n+", the sum is: "+sum);

Running results:

2. Assuming the annual interest rate of investment is 5%, how many years will it take to increase from 1,000 to 5,000?

var money=1000;
var i=0;
while(money<=5000){
	money=money*1.05;
	++i;
}
console.log("A total of "+i+" years is required");

Running results:

3. Find the daffodil number between 100 and 1000. A daffodil number is a 3-digit number where the sum of the 3 powers of each digit is equal to itself. For example, 1^3 + 5^3 + 3^3 = 153

for(var i=100;i<1000;i++){
	//Get the number in the hundreds place var a=parseInt(i/100);
	//Get the number in the tens place var b=parseInt(i/10%10);
	// Extract the number in the ones place var c=parseInt(i%10);
	 if(a*a*a+b*b*b+c*c*c==i){
	    console.log(i);
		}
}

The tens digit can also be obtained using var b=paraseInt((i-bai*100)/10).

Running results:

4. Print the sum of all odd numbers between 1-100. All numbers that are not divisible by 2 are odd numbers.

var sum=0;
for(var i=1;i<=100;i++){
	if(i%2==0){
		sum+=i;
	}
}
console.log("The sum of odd numbers is: "+sum);

Running results:

5. Determine the prime numbers between 2-100. A prime number is a natural number greater than 1 that cannot be divided by any other natural numbers except 1 and itself.

for(var i=2;i<=100;i++){
	var flag = true;
	//If the loop reaches i, there will be repeated factors for(var j=2;j<=Math.sqrt(i);j++){
		if(i%j==0){
			flag=false;
			break;
		}
	}
	if(flag==true){
		document.write(i+"&nbsp");
	}
}

Running results:

6. Printing triangle

From little to more

for(var i=1;i<=5;i++){
	for(var j=1;j<=i;j++){
		document.write("*");
	}
	document.write("<br/>");
} 

From more to less

for(var i=0;i<5;i++){
	for(var j=0;j<5-i;j++){
		document.write("*");
	}
	document.write("<br/>");
} 

7. Print the multiplication table

for(var i=1;i<=9;i++){
	for(var j=1;j<=i;j++){
		document.write(i+"*"+j+"="+i*j+"&nbsp;&nbsp;")
	}
	document.write("<br/>");//line break}

Running results:

This is the end of this article about javascript examples explaining the use of loops. For more relevant javascript loop content, please search for previous articles on 123WORDPRESS.COM or continue to browse the following related articles. I hope everyone will support 123WORDPRESS.COM in the future!

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