array-01.c

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

void main()
{
    int Max = 0;
    int i;
    float Number[20];
    float Summary;
    float Average;

    Summary = 0;
    printf("Please input the number of data : ");
    scanf("%d", &Max);
    if (Max < 20)
    {
        for (i = 0; i < Max; i++)
        {
            printf("Please input a number : ");
            scanf("%f", &Number[i]);
            Summary += Number[i];
        }
        Average = Summary / Max;
        printf("The average is %5.2f \n", Average);
     }
     else
        printf("Please input a number less than 20.");
}