Dividing only non floating point numbers-CodePudding

I want to divide a number x with a number from the array[] = {2,3,4,5,6,7,8,9}, so that the result is a clean number (non floating point number such as 1, 2 or 1033), I would like to avoid a result with decimal places (such as 1.23 , 535.222 or 111.111).

Example: x = 140

Which is the biggest number that can divide 140, so that the result is a non floating point number (an int)? Right It´s 7.

Which c method or procedure can I use?

Noting, because I don´t get a solution or any useful idea.

CodePudding user response：

You want to use the div( int numerator, int denominator) function. It returns a quotient and remainder for the division. If the remainder is zero then the numerator is perfectly divided by the denominator.

bool divides_perfectly( int numerator, int denominator )
{
    return ( div(numerator, denominator).rem == 0 )
}

CodePudding user response：

You might want to study this :

the C way of handling arrays of varrying length (std::vector)
make functions (to keep code readable)
never trust your input and do error handling (exceptions in this case)
use the standard library for common algorithms (like sorting)
use range based for loops (to not go out of bounds of an array, prevents bugs)
modulo operator, %, which will give you the remainder of a division

#include <algorithm>
#include <cassert>
#include <iostream>
#include <vector>
#include <stdexcept>

int greatest_divisor(const int value, std::vector<int> divisors) // explicitly copy values
{
    std::sort(divisors.begin(), divisors.end(), std::greater<int>());
    
    for (const int divisor : divisors)
    {
        if (value % divisor == 0) return divisor;
    }

    throw std::invalid_argument("no valid divisor found");
}


int main()
{
    std::vector<int> values{ 2,3,4,5,6,7,8,9 };
    int input_value{ 140 };

    try
    {
        auto divisor = greatest_divisor(input_value, values);
        std::cout << divisor;
        assert(divisor == 7);
    }
    catch (const std::exception& e)
    {
        std::cout << "error : " << e.what();
    }

    return 0;
}