Thing

// Author: Dave Wessels
// File:   lab5.cpp
// Purpose: drawing ascii boxes of a user chosen size in the range 1-80

// cstdio used for printf/scanf, cctype used for isspace
#include <cstdio>
#include <cctype>

// define the minimum and maximum sizes of the squares
const int MinSize = 1;
const int MaxSize = 80;

// define the characters used to print the box components
const char boxTopBot   = '-';
const char boxInternal = ' ';
const char boxSide     = '|';
const char boxCorner   = '+';

// prints the outline of a square using | - and + symbols,
//    where size specifies the number of characters per side
void printSquare(int size);

// display the program overview and instructions,
//    min/max give the minimum/maximum box sizes
void displayOverview(int min, int max);

// gets the user to enter an integer in a specific range
int getInteger(int min, int max);

int main()
{
   // display the program intro
   displayOverview(MinSize, MaxSize);

   // get the size of the desired square
   int size = getInteger(MinSize, MaxSize);

   // print the square
   printSquare(size);

   // terminate the program
   printf("\nBye!\n\n");
   return 0;
}

// gets the user to enter an integer in a specific range
int getInteger(int min, int max)
{
   int userVal;  // an integer value entered by the user
   int valsRead; // the number of integer values just read

   // validData is set to true once a valid integer has been obtained
   bool validData = false;

   // keep prompting the user and reading values until
   //    a valid integer is obtained
   do {
      // prompt the user and read their response
      printf("Please enter an integer in the range %d to %d\n", min, max);
      valsRead = scanf("%d", &userVal);

      // see if non-integer data was entered
      if (valsRead < 1) {
         // discard the next input field as bad input
         // and display an error message
         scanf("%*s");
         printf("***ERROR: that was not an integer, please try again\n\n");
      }

      // see if an out-of-range integer was entered
      else if ((userVal < min) || (userVal > max)) {
         // the input was out of bounds,
         // ignore it and display an error message
         printf("***ERROR: that was not an integer in the range %d to %d, ", min, max);
         printf("please try again\n\n");
      }

      // a valid integer was entered
      else {
         validData = true;
      }

   } while (!validData);

   // return the valid value once obtained
   return userVal;
}


// display the program overview and instructions,
//    min/max give the minimum/maximum box sizes
void displayOverview(int min, int max)
{
   printf("This program draws an ascii square of a user-chosen size\n");
   printf("The size must be an integer in the range %d..%d\n\n", min, max);
}


// prints the outline of a square using | - and + symbols,
//    where size specifies the number of characters per side
void printSquare(int size)
{
   // print a header
   printf("\nPRINTING A SQUARE OF SIZE %d: \n\n", size);

   // for each row
   //     for each column in that row
   //         if that position is a corner print +
   //         if that position is a top/bottom border print -
   //         if that position is a side border print |
   //         if that position is internal print a space
   //     print a newline after each row is completed
   for (int row = 0; row < size; row++) {

       for (int col = 0; col < size; col++) {

           // see if it is a top/bottom border (print +)
           if ((row == 0) || (row == (size-1))) {
              // if so, see if it is a corner
              if ((col == 0) || (col == (size-1))) {
                 printf("%c", boxCorner);
              }
              // otherwise print the - for a top/bottom border
              else {
                 printf("%c", boxTopBot);
              }
           }

           // if it isn't a top/bottom border,
           //    see if it is a side border (print |)
           else if ((col == 0) || (col == (size-1))) {
              printf("%c", boxSide);
           }

           // otherwise it is internal (print a space)
           else {
              printf("%c", boxInternal);
           }
       }
       // print a newline at the end of each row
       printf("\n");
   }

   // print an extra newline after the last row
   printf("\n");
}