C Primer Plus Chapter 10, question 14 3 × 5 array

Write a program , Prompt the user for input 3 Group number , Each group contains 5 individual double Number of types （ Assume that all users respond correctly , Non numeric data will not be entered ）. The procedure shall accomplish the following tasks ：

a. Store the data entered by the user in 3×5 In the ground array

b. Calculate each group （5 individual ） The average of the data

c. Calculate the average of all data

d. Find out 15 The maximum of the data

e. Print the results

Each task should be completed with a separate function （ Use variable length arrays as formal parameters ）. To complete the task b, To write a function that calculates and returns the average value of a one-dimensional array , Call this function with a loop 3 Time . For functions that handle other tasks , You should take the entire array as an argument , To complete the task c and d The function of should return the result to the calling function .

Here is the code ：

#include <stdio.h>

double average(int n, double arr[n]);
double max(int n, double arr[n]);
int main(void)
{
	double arr[3][5];
	int i;
	
	printf("Enter an array of 3x5 (double):");
	for(i = 0; i < 15; i++)
	scanf("%lf", (double *)arr + i);
	for(i = 0; i < 3; i++)
	printf("Average for each row is: %.2lf\n", average(5, (double *)(arr + i)));
	printf("Average for total is: %.2lf\n", average(15, (double *)arr));
	printf("The max in your array is: %.2lf\n", max(15, (double *)arr));
	return 0;
 } 
 
 double average(int n, double arr[n])
 {
 	double total = 0;
 	double * end = arr + n;
 	
 	while(arr < end)
 	total += *arr++;
 	return total / n;
 }
 
 double max(int n, double arr[n])
 {
 	double max = *arr;
 	double * end = arr + n;
 	
 	while(arr < end)
 	{
 		if(max < *arr)
 		max = *arr;
 		arr++;
	 }
	 return max;
 }