Triangle

#pragma warning(disable:4996)
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

#define PI 3.14159265

struct Triangle {
    double a, b, c;
    double alpha, beta, gamma;
    char a_filled, b_filled, c_filled;
    char alpha_filled, beta_filled, gamma_filled;
};

void input(struct Triangle* t) {
    printf("(a): ");
    scanf("%lf", &t->a);
    if (t->a > 0) t->a_filled = 1;

    printf("(b): ");
    scanf("%lf", &t->b);
    if (t->b > 0) t->b_filled = 1;

    printf("(c): ");
    scanf("%lf", &t->c);
    if (t->c > 0) t->c_filled = 1;

    printf("alpha: ");
    scanf("%lf", &t->alpha);
    if (t->alpha > 0) t->alpha_filled = 1;

    printf("beta: ");
    scanf("%lf", &t->beta);
    if (t->beta > 0) t->beta_filled = 1;

    printf("gamma: ");
    scanf("%lf", &t->gamma);
    if (t->gamma > 0) t->gamma_filled = 1;

}

void output(const struct Triangle* t) {
    printf("\na = %g, b = %g, c = %g\n", t->a, t->b, t->c);
    printf("alpha = %g, beta = %g, gamma = %g\n", t->alpha, t->beta, t->gamma);
}

bool isValidTriangle(struct Triangle* t) {
    return (((t->a + t->b > t->c) && (t->a + t->c > t->b) && (t->b + t->c > t->a)) || (t->alpha + t->beta + t->gamma > 180));
}

void missel(struct Triangle* t) {
    if (!isValidTriangle) {
        if (t->a_filled && t->b_filled && t->alpha_filled) {

            t->c = sqrt(pow(t->a, 2) + pow(t->b, 2) - 2 * t->a * t->b * cos(t->alpha * PI / 180));
            t->c_filled = 1;

            t->beta = asin(sin(t->alpha * PI / 180) * t->b / t->c) * 180 / PI;
            t->beta_filled = 1;

            t->gamma = 180 - t->alpha - t->beta;
            t->gamma_filled = 1;
        }
        else if (t->a_filled && t->c_filled && t->beta_filled) {

            t->b = sqrt(pow(t->a, 2) + pow(t->c, 2) - 2 * t->a * t->c * cos(t->beta * PI / 180));
            t->b_filled = 1;

            t->alpha = asin(sin(t->beta * PI / 180) * t->a / t->b) * 180 / PI;
            t->alpha_filled = 1;

            t->gamma = 180 - t->alpha - t->beta;
            t->gamma_filled = 1;
        }
        else if (t->b_filled && t->c_filled && t->gamma_filled) {

            t->a = sqrt(pow(t->b, 2) + pow(t->c, 2) - 2 * t->b * t->c * cos(t->gamma * PI / 180));
            t->a_filled = 1;

            t->beta = asin(sin(t->gamma * PI / 180) * t->b / t->a) * 180 / PI;
            t->beta_filled = 1;

            t->alpha = 180 - t->beta - t->gamma;
            t->alpha_filled = 1;
        }
        else {
            printf("Triangle doesn't exists\n");
        }
    }
    else {
        printf("Triangle doesn't exists\n");
    }
}

int main() {

    struct Triangle t;
    memset(&t, 0, sizeof(t));
    input(&t);
    output(&t);
    missel(&t);

    if (!isValidTriangle) output(&t);

}