lab12.c

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <math.h>

int random(int min, int max)
{
    int tmp;
    if (max>=min)
        max-= min;
    else
    {
        tmp= min - max;
        min= max;
        max= tmp;
    }
    return max ? (rand() % max + min) : min;
}

struct vector {
    float x;
};

struct particle {
  float mass;
  struct vector position;
  struct vector velocity;
};

float vector_len(struct vector * v) {
    return sqrt(pow(v->x, 2));
}

float particle_momentum(struct particle * ptr) {
    return ptr->mass * vector_len(&ptr->velocity);
}

float particle_energy(struct particle * ptr) {
    return 0.5* ptr->mass * pow(vector_len(&ptr->velocity), 2);
}

void print_particle(struct particle * ptr) {
  printf("\nmass: %f\n", ptr->mass);
  printf("speed: %f\n", vector_len(&ptr->velocity));
  printf("position: %f\n", ptr->position.x);
  printf("momentum: %f\n", particle_momentum(ptr));
  printf("energy: %f\n", particle_energy(ptr));
}



int main() {
        struct particle * particles;
        int p_len;

        srand(time(NULL));

        scanf("%i", & p_len);

        particles = calloc(p_len, sizeof(struct particle));

        int i;
        double total_e = 0, total_m = 0;
        for (i = 0; i<p_len; i++) {
            particles[i].mass = random(0, 999);
            particles[i].velocity.x = random(-100, 100);
            particles[i].position.x = random(-100, 100);

            print_particle(&particles[i]);

            total_m += particle_momentum(&particles[i]);
            total_e += particle_energy(&particles[i]);
        }

        printf("total momentum: %f\n", total_m);
        printf("total energy: %f\n", total_e);


        free(particles);

        return EXIT_SUCCESS;
}