Untitled

#include <stdio.h>
#include <math.h>  
#define pi 3.14159265358979323846
#define half 90
#define pol 180
int main()
{
    double x, a = (-1), chisl, znam, sin = 0, cos = 0, chisl1, znam1;

    printf("enter x in degrees: ");
    if (scanf_s("%lf", &x) == 1)
    {

        while (x >= pol || x <= -pol)
        {
            if (x >= pol) x -= pol;
            else x += pol;
        }

        if(x == 90 || x == -90) printf("tg not exist");

        else
        {
            printf("%lf", x);
            printf("\n");
            if (x < 180 && x > -180)
            {
                x = (x * pi) / pol;
                for (int i = 0; i < 100; i++)
                {
                    if (i % 2 == 1)
                        a = 1;
                    else
                        a = -1;
                    znam = 1; chisl = 1; znam1 = 1; chisl1 = 1;
                    for (int j = (2 * i + 1); j > 0; j--)
                    {
                        znam *= j;
                        chisl *= x;
                    }
                    for (int y = (2 * i); y > 0; y--)
                    {
                        znam1 *= y;
                        chisl1 *= x;
                    }
                    cos += (a * (chisl1 / znam1));
                    sin += (a * (chisl / znam));
                }
                printf("tg=%lf", sin / cos);
            }
        }
    }
    else
    {
        printf("you didn't enter a number\n");
    }
    return 0;
}