Помогите, пожалуйста, написать программу на языке Си

#include <stdio.h>
#include <locale.h>
#include <math.h>
typedef unsigned long long ullong;
ullong factorial(ullong n);
double get_x(char* prompt, double left, double right);
double sum_series(double x, double eps);
int main(void) {
double x, s, test;
setlocale(LC_CTYPE, "Russian");
x = get_x(" Введите х: ", 0, 1);
s = sum_series(x, 1e-4);
test = pow(3, x);
printf(" Тест: %.15lf\n Сумм: %.15lf\n", test, s);
fflush(stdin);
getchar();
}
double sum_series(double x, double eps) {
double s = 0;
double member;
int n = 0;
do {
member = pow(log(3), n) * pow(x, n) / factorial(n);
s += member;
++n;
} while (eps <= member);
return s;
}
ullong factorial(ullong n) {
return n == 0? 1 : n * factorial(n - 1);
}
double get_x(char* prompt, double left, double right) {
double x;
if (left > right) {
double temp = left;
left = right;
right = temp;
}
do {
printf("%s", prompt);
while (!scanf_s("%lf", &x)) {
fflush(stdin);
printf("%s", prompt);
}
} while (x < left || x > right);
return x;
}

Держите:

$ cat 3x.c
#include <stdio.h>
#include <math.h>
#define EPSILON 0.0001
int main () {
int i = 1;
double x, sum = 0, m = 1;
scanf ("%lf", &x);
if (x < 0 || x > 1) return 1;
do {
  sum += m;
  m = m * log(3) / i * x;
  i++;
} while (fabs (m) > EPSILON);
printf ("%.4lf, %.4lf\n", sum, pow (3, x));
return 0;
}

Компиляция:

$ clang 3x.c -o 3x -lm

Проверка:

$ echo .5 | ./3x
1.7320, 1.7321