A simple program to compute compound interest using loops and printing the result on CLI.

compound_interest.cpp

// in this program we are going to be calculating compound interest using a looping
// algorithm.
//
// firstly, we discuss the solution that we have in mind. since we are required to
// compute this without a formula but using loops we are going to define a function
// that will represent the function call.
//

// let us start by getting the resources we are going to need
#include <iostream>

// then we start defining our function here
double compoundInterest(int invest, double years, double annualRate) {
    double interest = 1;
    for (; years > 0; years--) {
        interest *= (1 + annualRate);
    }

    return invest * interest;
}

// we define an assertion function that will assert that a number n is real and between
// 0 and 100
void assertReal(int n) {
    if (n < 0 || n > 100) {
        throw ("Value is Not a Real Number");
    }
}

// okay, now with the function defined all we are going to need to do is apply it.
int main()
{
    // let us consider the problem statement that we are given. we are required to compute
    // the interest of a E100 investment with interst of 5%, we are to print the interest
    // accumulated after 10years

    // so let us make a functionality to allow a user to enter the values that will then be
    // computed here. considering the problem, we are required to enter only the interest rate
    // so we will make a prompt for just that
    int rate = 0;

    // we will cout a prompt so that user knows what to enter
    std::cout << "Please enter your anual interest rate below" << std::endl;
    std::cin >> rate;

    // once the interest rate is entered we should validate it to make sure that the value is a
    // real number between 0 and 100 percent;
    assertReal(rate);
    

    std::cout << "Compound Interest After 10 Years - " << compoundInterest(100, 10, (double)rate / 100) << std::endl;

    return 0;
}

I will put the first task 2 for your comments

Cool cool