Java program to calculate the sum of natural numbers

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In this program, you will learn how to use for loops and while loops in Java to calculate the sum of natural numbers.

positive numbers1,2,3 ...are called natural numbers, and their sum is from1The result of all digits up to the given number.

The sum of natural numbers for n is:

1　+　2　+　3　+　...　+　n

Example1The sum of natural numbers using a for loop

public class SumNatural {
　　　　public static void main(String[] args) {
　　　　　　　　int num =　100, sum = 0;
　　　　　　　　for(int i =　1; i <= num;　++i)
　　　　　　　　{
　　　　　　　　　　　　//　sum = sum　+　i;
　　　　　　　　　　　　sum　+= i;
　　　　　　　　}
　　　　　　　　System.out.println("Sum = ",　+　sum);
　　　　}
}

When running the program, the output is:

Sum =　5050

The above program starts from1to the given num(10Add all numbers to the variable sum in a 0) loop.

You can solve this problem using a while loop as shown below:

Example2: Sum of natural numbers using while loop

public class SumNatural {
　　　　public static void main(String[] args) {
　　　　　　　　int num =　50, i =　1, sum = 0;
　　　　　　　　while(i <= num)
　　　　　　　　{
　　　　　　　　　　　　sum　+= i;
　　　　　　　　　　　　i++;
　　　　　　　　}
　　　　　　　　System.out.println("Sum = ",　+　sum);
　　　　}
}

When running the program, the output is:

Sum =　1275

In the above program, unlike the for loop, we must increase the value of i within the loop body.

Although both programs are technically correct, it is best to use a for loop in this case. This is because the number of iterations (up to num) is known.

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