# How to write a C program to find and sum all numbers divisible by 9 between 100

## Introduction

Welcome to our comprehensive guide on finding and summing all numbers divisible by 9 between 100 and a user input in a C program. In this article, we will provide you with a step-by-step approach to solve this problem efficiently and effectively. By following our instructions, you will be able to create a high-performing C program that not only solves the task at hand but also stands out from the competition. So, let’s dive right in!

## Understanding the Problem

Before we start writing the code, it’s essential to have a clear understanding of the problem statement. We are tasked with finding and summing all numbers that are divisible by 9 within a specific range. The lower bound of the range is fixed at 100, while the upper bound will be determined by the user’s input.

## Algorithm

To accomplish our goal, we will follow a systematic algorithm that ensures accuracy and efficiency in our program. Here are the steps we will take:

### Step 1: Accept User Input

We begin by taking input from the user to determine the upper bound of the range. This value will be stored in a variable for later use.

### Step 2: Initialize Variables

Next, we initialize a variable to hold the sum of the divisible numbers and another variable to iterate through the range starting from 100.

### Step 3: Iterate Through the Range

Using a loop, we iterate through the range of numbers starting from 100 up to the user-defined upper bound. For each number, we check if it is divisible by 9 using the modulo operator (%). If the number is divisible, we add it to the sum variable.

### Step 4: Display the Result

Once the loop has finished iterating through the range, we display the final sum of all the divisible numbers to the user.

## How to write a C program to find and sum all numbers divisible by 9 between 100

## Implementation

**Example 1:**

Now that we have a clear algorithm in mind, let’s implement it in C code. Here’s a sample implementation that you can use as a reference:

```
#include <stdio.h>
int main() {
int userInput, sum = 0;
printf("Enter the upper bound: ");
scanf("%d", &userInput);
for (int i = 100; i <= userInput; i++) {
if (i % 9 == 0) {
sum += i;
}
}
printf("The sum of numbers divisible by 9 between 100 and %d is: %d\n", userInput, sum);
return 0;
}
```

**Example 2:**

#include<stdio.h> void main () { int i,n,disvi=1,sum=0; scanf ("%d",&n); printf("Numbers between 100 and 200:"); for (i=100;i<=n;i++){ if(disvi=(i%9==0)){ printf(" %d ",i); sum=i+sum; } } printf("\nThe sum:%d",sum); }

## Conclusion

Congratulations! You have successfully created a C program that finds and sums all the numbers divisible by 9 between 100 and the user input. By following the steps outlined in this article, you now have a competitive advantage in outranking other websites offering similar content.

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