##### C program to calculate Compound Interest

Here’s a simple C program that prints a message on the screen:

```				```
#include <stdio.h>
#include <math.h>

int main() {
double principal, rate, time, compoundInterest;

printf("Enter the principal amount: ");
scanf("%lf", &principal);

printf("Enter the annual interest rate: ");
scanf("%lf", &rate);

printf("Enter the time in years: ");
scanf("%lf", &time);

compoundInterest = principal * pow((1 + rate/100), time);

printf("Compound interest is: %.2lf\n", compoundInterest);

return 0;
}

```
```
##### Output
• Explanation:

• The program starts by including the `stdio.h` and `math.h` header files. `stdio.h` is needed for input and output operations, while `math.h` is needed for the `pow` function used to calculate the exponentiation.
• Inside the `main` function, we declare the variables `principal`, `rate`, `time`, and `compoundInterest` as doubles to store the respective values.
• We then prompt the user to enter the principal amount, annual interest rate, and time in years using `printf` statements, and we read their input using `scanf` statements.
• The compound interest is calculated using the formula: `compoundInterest = principal * pow((1 + rate/100), time)`. The `pow` function is used to calculate the exponentiation of `(1 + rate/100)` to the power of `time`.
• Finally, we use a `printf` statement to display the calculated compound interest with two decimal places.

When you run this program, it will prompt you to enter the principal amount, annual interest rate, and time in years. After you provide the inputs, it will calculate and display the compound interest.