lab1_3

#include <stdio.h>

/* Exponent calculating with eps accuracy, 0<eps<1 */

int fact(int num);
int cntNum(double num);

main()
{
    double eps, summand = 1.0, exp = 0.0;
    int n = 0, size;

    puts("enter epsilon's value");
    scanf("%g", &eps);

    while (summand > eps) {
        summand = 1.0 / fact(n);
        exp += summand;
        ++n;
    }

    size = cntNum(eps);
    printf("%.*g\n", size, exp);

    return 0;
}

int fact(int num)
{
    int i;
    long factNum = 1;

    for (i = 1; i <= num; ++i)
        factNum *= i;

    return factNum;
}

int cntNum(double num)
{
    int i = 0;

    while (num != 1) {
        num *= 10;
        ++i;
    }
    return i;
}