This C program adds three numbers entered by the user, finds their average up to two decimal places and then prints the results.

**Prerequisite knowledge:**

- Basic syntax.
- Average of 3 numbers = sum of the numbers/3

**Program:** C program to calculate the sum and average of three numbers

#include<stdio.h>intmain() {inta,b,c,sum;floatavg; printf("Enter three numbers: "); scanf("%d %d %d",&a,&b,&c); sum=a+b+c; /*calculating sum*/ avg=sum/3; /*calculating average*/ printf("\nSum: %d \nAverage: %.2f\n",sum,avg); return 0; }

**Output:**

```
Enter three numbers: 15 17 13
Sum: 45
Average: 15.00
```

The sum and average of three numbers can also be calculated using **functions**. Below is the code for that. To understand the program, you should know about functions in C.

### Program 2: C program to find sum and average of three numbers using function

#include<stdio.h>intsum(int,int,int);floatavg(int,int,int);intmain() {inta,b,c; printf("Enter three numbers: "); scanf("%d %d %d",&a,&b,&c); printf("Sum: %d \nAverage: %.2f\n",sum(a,b,c),avg(a,b,c)); return 0; }intsum(inta,intb,intc) { returna+b+c; //calculate and return the sum }floatavg(inta,intb,intc) { return (a+b+c)/3; //calculate and return the average }

**Output:**

```
Enter three numbers: 10 20 60
Sum: 90
Average: 30.00
```

That’s it, this is the code.

In this article, we learnt how to find the sum and average of three numbers in C using functions and without using functions.

Do share your code in the comment section to help others. You’re going to make it big one day.

If you didn’t understand the concept fully, you can learn from the YouTube video below: