struct_esqueleto.c

#include <stdio.h>
#include <math.h>
#define MAX_ALUNOS 20

typedef float prova;
typedef float media;

struct provas{
  prova p[3];
  media M;
};
typedef struct provas Provas;

struct aluno{
  char ra[7];
  int frequencia;
  Provas Ps;
};

int main(void)
{
  int n,i,j;
  float desvios_Ps[3]={0.0,0.0,0.0},medias_Ps[3]={0.0,0.0,0.0};
  struct aluno alunos[MAX_ALUNOS];

  printf("Insira o número de alunos.\n");
  scanf("%d",&n);

  for(i=0;i<n;i++){
    printf("Insira o RA do aluno.\n");
    fgets(alunos[i].ra,7,stdin);
    printf("Insira as notas das provas.\n");
    for(j=0;j<3;j++){
      scanf("%f",&alunos[i].Ps.p[j]);
    }
    while(getchar()!='\n');
  }

  for(i=0;i<n;i++){
    printf("RA: %s\n",alunos[i].ra);
    printf("Prova 0: %.2f\n",alunos[i].Ps.p[0]);
    printf("Prova 1: %.2f\n",alunos[i].Ps.p[1]);
    printf("Prova 2: %.2f\n",alunos[i].Ps.p[2]);
    alunos[i].Ps.M=0;
    for(j=0;j<3;j++){
      alunos[i].Ps.M+=alunos[i].Ps.p[j];
    }
    alunos[i].Ps.M/=3;
    printf("Media: %.2f\n",alunos[i].Ps.M);
    printf("\n");
  }

  for(i=0;i<3;i++){
    for(j=0;j<n;j++){
      medias_Ps[i]+=alunos[j].Ps.p[i];
      desvios_Ps[i]+=((alunos[j].Ps.p[i]-alunos[j].Ps.M)*(alunos[j].Ps.p[i]-alunos[j].Ps.M));
    }
    medias_Ps[i]/=n;
    desvios_Ps[i]/=3;
    desvios_Ps[i]=sqrt(desvios_Ps[i]);
    printf("Media Geral P%d: %.2f\n",i,medias_Ps[i]);
    printf("Devio padrao P%d: %.2f\n",i,desvios_Ps[i]);
  }

  return 0;
}