Print Reverse array of Max size 20 - arrays

Question

#include <stdio.h>
void ArrayReverese(int a[], int Start, int End);
void printArray(int a[], int Size);
int main()
{
int a[20], i, Size;
int max_size = 20;
printf("\nPlease Enter the size of an array: ");
scanf_s("%d", &Size);
while (Size <= 20)
{
//Inserting elements into the Declared Array
for (i = 0; i < Size; i++)
{
scanf_s("%d", &a[i]);
}
ArrayReverese(a, 0, Size - 1); //Array Reverse
printf("Result of an Reverse array is: \n");
printArray(a, Size); //Printing Array
return 0;
}
printf("Max size of array is 20");
}
/* Function to Reverse the Given Array */
void ArrayReverese(int a[], int Start, int End)
{
int Temp;
while (Start < End)
{
Temp = a[Start];
a[Start] = a[End];
a[End] = Temp;
Start++;
End--;
}
}
/* Function to print the Array Output */
void printArray(int a[], int Size)
{
int i;
for (i = 0; i < Size; i++)
{
printf("%d ", a[i]);
}
printf("\n");
}
I am writing code to print the output of a reverse array. The max size of the array can only be 20. I have put a while loop of max_size = 20.
Is this the best way to not let the array be greater than 20?
What does the a[20] help? Does it make for max size?

Answer 1

Is this the best way to not let the array be greater than 20?
I believe that the best option would be to make sure that the inputed size is in the required interval. You would need something similar to this (explanation in the comments):
int main(){
int a[20], Size = 0;
int max_size = 20;
printf("\nPlease Enter the size of an array: ");
// loop keeps asking for a size if it's not in the interval
do
{
int ret = scanf_s("%d", &Size);
if(ret != 1){ // if the input is not parsed correctly...
printf("Bad input. ");
int c;
while((c = getchar()) != '\n' && c != EOF ) {} // clear the buffer...
}
// size must be more than 0 and less than 20, if not ask again
} while (Size >= max_size && Size < 1 && printf("Max size of array is 20, try again: "));
// Size is guaranteed to be [1, 20[ no further checks needed here
for (int i = 0; i < Size; i++)
{
scanf_s("%d", &a[i]); // check the return of this scanf also
}
ArrayReverese(a, 0, Size - 1); //Array Reverse
printf("Result of an Reverse array is: \n");
printArray(a, Size); //Printing Array
}
What does the a[20] help? Does it make for max size?
An array must have a size, in this case is 20, and that is its maximum size, but that doesn't stop it from being overrun, it's up to the programmer to prevent this from happening, as shown in the code above.