Thread: Calculate E

I am trying to make a program to calculate E.
I finished, but it kept returning
2.000000
I've looked over this code many times and I can't find an apparent problem.
Here is the code:

Code:

// e_calculate.cpp : Defines the entry point for the console application.//


#include "stdafx.h"




int main()
{
    printf("Enter an integer here\n/");
    int num;
    double e;
    int factorial, count, count2;
    count = 0;
    count2 = 0;
    factorial = 0;
    scanf("%d", &num);
    e = 1;
    while (num > count)
    {
        count = count + 1;
        factorial = count;
        while (count > count2)
        {
            count2 = count2 + 1;
            factorial = factorial * count2;
        }
        count2 = 0;
        e = e + (1 / factorial);
    }
    printf("%f", e);
    return 0;
}

Code:

e = e + (1 / factorial);

"factorial" is an int, so "1 / factorial" produces a truncated integer quotient.

Try "1.0 / factorial" instead.

Originally Posted by www.infysim.org

I think you need to convert the integer values to double by typecasting and see what happens.

Only one of the operands to the division has to be double, which will cause the other operand to be automatically promoted to double*. Since one of the operands is a constant, the OP can avoid type-casting by explicitly making that constant a double, as I illustrated. If both operands were variables, then a type-cast would be necessary.

* See "6.3.1.8 Usual arithmetic conversions" in the specification.