Output student grades

This question requires the preparation of procedures , According to the input student's score , Count and output the average score of students 、 Top and bottom . Dynamic memory allocation is recommended for .

Input format ：

Enter the first line to first give a positive integer N, Number of students . The next line shows N Results of students , Numbers are separated by spaces .

Output format ：

Output in the following format ：

average =  Average score 
max =  Top grade 
min =  Minimum score 

Keep two decimal places for results .

sample input ：

3
85 90 95

sample output ：

average = 90.00
max = 95.00
min = 85.00

Code ： 

#include <stdio.h>
int main(){
    int N;
    scanf("%d",&N);
    double a[N];
    double average,max,min,sum=0;
    int i,j;
    for(i=0;i<N;i++){
        scanf("%lf",&a[i]);
        sum=sum+a[i];
    }
    average=sum/N;
    max=a[0];
    for(i=0;i<N-1;i++){
        if(max<a[i+1])max=a[i+1];
        }
    min=a[0];
    for(i=0;i<N-1;i++){
        if(min>a[i+1])min=a[i+1];
    }
    printf("average = %.2lf\nmax = %.2lf\nmin = %.2lf",average,max,min);
    }