 # PHP Program to find the sum of n natural number

October 14, 2021, Learn eTutorial
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## How to calculate the sum of n natural numbers using PHP?

In this program, we are going to find the sum of the n natural number. For that we first have to read the n number into the variable num. after that we have to assign that to the variable n and also assign the value 0 to the variable sum. Then we have to perform the while loop until the condition 'n >= 0' becomes false and in the block of the loop, we have to assign the computed value of 'sum + n' to the variable n and decrement the value of the variable n. After the completion of the loop, we have to print the value of the variable sum as the sum of the n natural number. For example, if the entered number is 5 then the result will be 1+2+3+4+5 = 15

### ALGORITHM

Step 1: Accept the number from the user and insert it into the variable num

Step 2: Assign the value of variable num into the variable n and assign the value 0 into the variable sum

Step 3: Perform the following sub-steps until the condition 'n >= 0'

(i) Assign the calculated value of 'sum + n' into the variable sum

(ii) Decrement the value of the variable n

Step 4: Print the value of the variable sum as the sum of n natural number

## PHP Source Code

```                                          ```<?php
\$num = readline("Enter the n number: ");
\$n = \$num;
\$sum = 0;
while (\$n >= 0) {
\$sum = \$sum + \$n;
\$n--;
}
echo "Sum of \$num number is: \$sum";
?>```
```

## OUTPUT

```Enter the number: 10
Sum of 10 number is: 55```