squares.h

   1
   2 #include "basics.h"
   3 #include <math.h>
   4
   5 int is_even (int num)
   6 {
   7   return (num % 2);
   8 }
   9
  10 char* inside_out (char* string)
  11 {
  12   int length = strlen(string);
  13   int center = is_even(length);
  14   char* result = calloc(sizeof(char), length + 1); // for NUL
  15   int half = (length / 2) - 1; // account for 0-index
  16
  17   for (int i = 0; i < length; i++)
  18     {
  19       if (i == half)
  20         result[i] = string[0];
  21
  22       else if (center && (i == (half + 1)))
  23         result[i] = string[half + 1];
  24
  25       else if (i == (half + 1 + center))
  26         result[i] = string[length - 1];
  27
  28       else if (i <= half)
  29         result[i] = string[i + 1];
  30
  31       else
  32         result[i] = string[i - 1];
  33     }
  34
  35   return result;
  36 }
  37
  38
  39 char* generate_square(char* string)
  40 {
  41   int length = strlen(string);
  42   // The size is for the square, the newlines and the NUL-term
  43   int result_size = (length * length) + length;
  44   char* result = calloc(sizeof(char), result_size);
  45
  46   char* current = string;
  47   int count = 0;
  48   int index = 0;
  49   for (index = 0; index < (result_size / 2); index++)
  50     {
  51       if (count == length)
  52         {
  53           result[index] = '\n';
  54           current = inside_out(current);
  55           count = 0;
  56         }
  57
  58       else
  59         {
  60           result[index] = current[count];
  61           count++;
  62         }
  63     }
  64
  65   count = (result_size / 2) - 1;
  66   for (index = (result_size / 2) - 1; index < result_size; index++)
  67     {
  68       // printf("\nprocessing half...\n");
  69       result[index] = result[count];
  70       count--;
  71     }
  72
  73   return result;
  74 }