testscore

#include <stdio.h>
#include <string.h>
#include <math.h>
typedef struct
{
    char name[21];
    float score;
    int num;
    char grade;
}student;
int input(student s[100]);
float average(student s[100],int num);
float sigma(student s[100],int num, float avg);
void decision(student s[100],int num, float avg,float sd);
void output(student s[100],int num);
int main()
{
    int num;
    float avg,sd;
    student std[100];
    num=input(std);
    avg=average(std,num);
    sd=sigma(std,num,avg);
    decision(std,num,avg,sd);
    output(std,num);
    system("PAUSE");
    return 0;
}

int input(student s[100])
{
    int i,num;
    printf("Number of students : ");
    scanf("%d",&num);
    for(i=0;i<num;i++)
    {
        printf("Neme #%d : ",i+1);
        scanf("%s",s[i].name);
        printf("Score #%d : ",i+1);
        scanf("%f",&s[i].score);
        printf("Attend #%d : ",i+1);
        scanf("%d",&s[i].num);
    }
    return num;
}

float average(student s[100],int num)
{
    int i;
    float sum=0,avg=0;
    for(i=0;i<num;i++)
    {
        sum+=s[i].score;
    }
    avg=sum/num;
    printf("SCORE AVERAGE = %.2f\n", avg);
    return avg;
}

float sigma(student s[100],int num, float avg)
{
    int i;
    float sum=0,sd=0;
    for(i=0;i<num;i++)
    {
        sum+=(s[i].score-avg)*(s[i].score-avg);
    }
    sd=sqrt(sum/num);
    printf("SCORE SD = %.2f\n",sd);
    return sd;
}

void decision(student s[100],int num, float avg,float sd)
{
    int i;
    for(i=0;i<num;i++)
    {
        if(s[i].score>avg&&s[i].score>sd&&s[i].num>0.8*45)
        {
            s[i].grade='G';
        }
        else if(s[i].score>avg&&s[i].num>0.5*45)
        {
            s[i].grade='P';
        }
        else
        {
            s[i].grade='F';
        }
    }
}

void output(student s[100],int num)
{
    int i,g=0,p=0,f=0;
    printf("-----------------------------\n");
    printf("Name\t Score\t Attend\t Grade\n");
    printf("-----------------------------\n");
    for(i=0;i<num;i++)
    {
        printf("%s\t %.2f\t %d\t %c\n",s[i].name,s[i].score,s[i].num,s[i].grade);
    if(s[i].grade=='G')
    {
        g++;
    }
    else if (s[i].grade=='P')
    {
        p++;
    }
    else if(s[i].grade=='F')
    {
        f++;
    }
}
    printf("-----------------------------\n");
    printf("GOOD=%d, PASS=%d, FAIL=%d\n", g, p, f);
    printf("-----------------------------\n");

}