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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <assert.h>
  4.  
  5. // supported N = 26
  6. char canvas[ 26 * 2 - 1 ][ 26 * 2 - 1 ];
  7.  
  8. void draw_triangle( int n, char c, int x, int y ) {
  9.  
  10.     int line_length = n * 2 - 1;
  11.  
  12.     // draw n lines
  13.     for( ; 0 < n; --n ) {
  14.         // draw a line with specific length
  15.         for( int len = 0; len < line_length; ++len )
  16.         {
  17.             canvas[ y ][ x + len ] = c;
  18.         }
  19.         --y, ++x;
  20.         line_length -= 2;
  21.     }
  22. }
  23.  
  24. void draw_upside_down_triangle( int n, char c, int x, int y ) {
  25.  
  26.     int line_length = n * 2 - 1;
  27.  
  28.     // draw n lines
  29.     for( ; 0 < n; --n ) {
  30.         // draw a line with specific length
  31.         for( int len = 0; len < line_length; ++len )
  32.         {
  33.             canvas[ y ][ x + len ] = c;
  34.         }
  35.         ++y, ++x;
  36.         line_length -= 2;
  37.     }
  38. }
  39.  
  40.  
  41. int main() {
  42.  
  43.     int n;
  44.     scanf( "%d", &n );
  45.     assert( 0 < n && n <= 26 );
  46.  
  47.     int used_width = n * 2 - 1;
  48.     int used_height = n * 2 - 1;
  49.  
  50.     // clear canvas content
  51.     for( int row = 0; row < used_height; ++row ) {
  52.         for( int col = 0; col < used_width; ++col ) {
  53.             canvas[ row ][ col ] = ' ';
  54.         }
  55.     }
  56.  
  57.     int start_x = 0,
  58.         start_y = n - 1;
  59.     char c = 'A';
  60.     for( ; 0 < n; --n ) {
  61.         draw_triangle( n, c, start_x, start_y );
  62.         draw_upside_down_triangle( n, c, start_x, start_y );
  63.         ++start_x;
  64.         ++c;
  65.     }
  66.  
  67.     // print the canvas
  68.     for( int row = 0; row < used_height; ++row ) {
  69.         for( int col = 0; col < used_width; ++col ) {
  70.             printf( "%c", canvas[ row ][ col ] );
  71.         }
  72.         printf("\n");
  73.     }
  74.  
  75.     return EXIT_SUCCESS;
  76. }
Runtime error #stdin #stdout 0.02s 1808KB
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https://ideone.com/BgGy7f
language:
C99 (gcc 8.3)
created:
13 years ago
visibility:
public

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