Pileus Git - ~andy/sfvlug/blob - c/src/data.c

   1 #include <stdio.h>
   2 #include <stdint.h>
   3
   4 int main()
   5 {
   6         /*
   7          * Numeric types.
   8          */
   9         int the_answer = 42;
  10
  11         signed negative = -100;
  12
  13         unsigned positive = 100;
  14
  15         long long trillion = 1000000000000;
  16
  17         unsigned long long int neg_trillion = -1000000000000;
  18
  19         short two_bytes = 65000;
  20
  21         char one_byte = 123;
  22
  23         printf("Numbers\n");
  24         printf("  the_answer   = %d\n",   the_answer);
  25         printf("  positive     = %d\n",   positive);
  26         printf("  negative     = %u\n",   negative);
  27         printf("  trillion     = %lld\n", trillion);
  28         printf("  neg_trillion = %lld\n", neg_trillion);
  29         printf("  two_bytes    = %hd\n",  two_bytes);
  30         printf("  one_byte     = %hhd\n", one_byte);
  31         printf("\n");
  32
  33         /*
  34          * Standard integers.
  35          */
  36         int8_t signed_8bit = 1;
  37
  38         uint8_t unsigned_8bit = 2;
  39
  40         int64_t signed_64bit = 3;
  41
  42         uint64_t unsigned_64bit = 4;
  43
  44         printf("Standard Ints\n");
  45         printf("  signed_8bit    = %hhd\n", signed_8bit);
  46         printf("  unsigned_8bit  = %hhu\n", unsigned_8bit);
  47         printf("  signed_6bit_   = %ld\n",  signed_64bit);
  48         printf("  unsigned_64bit = %lu\n",  unsigned_64bit);
  49         printf("\n");
  50
  51         /*
  52          * Characeters.
  53          */
  54         char a_char = 'a';
  55
  56         char a_int = 97;
  57
  58         char a_hex = 0x61;
  59
  60         printf("Standard Ints\n");
  61         printf("  as integers = %2d %2d %2d\n", a_char, a_int, a_hex);
  62         printf("  as chars    = %2c %2c %2c\n", a_char, a_int, a_hex);
  63         printf("  as hex      = %2x %2x %2x\n", a_char, a_int, a_hex);
  64         printf("\n");
  65
  66         /*
  67          * Arrays.
  68          */
  69         int fixed_size[100] = {1, 2, 3};
  70
  71         int auto_sized[] = {1, 2, 3};
  72
  73         int tables[][32] = {
  74                 {1, 2, 3},
  75                 {4, 5, 6},
  76         };
  77
  78         printf("Array sizes\n");
  79         printf("  fixed_size  = %zd\n", sizeof(fixed_size));
  80         printf("  auto_sized  = %zd\n", sizeof(auto_sized));
  81         printf("  table size  = %zd\n", sizeof(tables));
  82         printf("  first       = %d\n",  fixed_size[0]);
  83         printf("  third       = %d\n",  fixed_size[2]);
  84         printf("  last        = %d\n",  fixed_size[99]);
  85         printf("  tables      = %d\n",  tables[0][0]);
  86         printf("\n");
  87
  88         /*
  89          * Strings.
  90          */
  91         char hello_char[] = {'h', 'e', 'l', 'l', 'o', '\0'};
  92
  93         char hello_str[] = "hello";
  94
  95         char *hello_ptr = "hello";
  96
  97         printf("Strings\n");
  98         printf("  as strings  = %s %s %s\n",
  99                         hello_char,
 100                         hello_str,
 101                         hello_ptr);
 102         printf("  as arrays   = %c %c %c\n",
 103                         hello_char[0],
 104                         hello_str[0],
 105                         hello_ptr[0]);
 106         printf("  sizes       = %zd %zd %zd\n",
 107                         sizeof(hello_char),
 108                         sizeof(hello_str),
 109                         sizeof(hello_ptr));
 110         printf("\n");
 111
 112         /*
 113          * Pointers.
 114          */
 115         int one = 1;
 116
 117         int two = 2;
 118
 119         int *pointer = &one;
 120
 121         *pointer = 100;
 122
 123         printf("Strings\n");
 124         printf("  one      = %d\n",   one);
 125         printf("  two      = %d\n",   two);
 126         printf("  pointer  = %llx\n", (long long)pointer);
 127         printf("  pointer  = %p\n",   pointer);
 128         printf("  value    = %d\n",   *pointer);
 129
 130
 131         return 0;
 132 }