| Last change
 on this file since 089b39e1 was             df699e0, checked in by Peter A. Buhr <pabuhr@…>, 18 months ago | 
        
          | 
program updates to match text
 | 
        
          | 
              
Property                 mode
 set to                 100644 | 
        
          | File size:
            1.4 KB | 
      
      
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| 1 | #include <stdio.h> | 
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| 2 | #include <assert.h> | 
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| 3 | #include <stdlib.h> | 
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| 4 |  | 
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| 5 | #define SHOW(x, fmt) printf( #x ": " fmt "\n", x ) | 
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| 6 |  | 
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| 7 | #ifdef ERRS | 
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| 8 | #define ERR(...) __VA_ARGS__ | 
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| 9 | #else | 
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| 10 | #define ERR(...) | 
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| 11 | #endif | 
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| 12 |  | 
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| 13 |  | 
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| 14 |  | 
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| 15 | int main() { | 
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| 16 | float ar[3][10]; | 
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| 17 | static_assert(sizeof(float) == 4);                      $\C{// floats (atomic elements) are 4 bytes}$ | 
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| 18 | static_assert(sizeof(void*) == 8);                      $\C{// pointers are 8 bytes}$ | 
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| 19 |  | 
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| 20 | static_assert(sizeof(ar) == 120);                       $\C{// the array, float[3][10]}$ | 
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| 21 | static_assert(sizeof(ar[0]) == 40);                     $\C{// its first element, float[10]}$ | 
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| 22 | static_assert(sizeof(ar[0][0]) == 4);           $\C{// its first grand element, float}$ | 
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| 23 |  | 
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| 24 | static_assert(sizeof(&(ar)) == 8);                      $\C{// pointer to the array, float(*)[3][10]}$ | 
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| 25 | static_assert(sizeof(&(ar[0])) == 8);           $\C{// pointer to its first element, float(*)[10]}$ | 
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| 26 | static_assert(sizeof(&(ar[0][0])) == 8);        $\C{// pointer to its first grand-element, float*}$ | 
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| 27 |  | 
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| 28 | float (*pa)[3][10] = &(ar); | 
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| 29 | float (*pa0)[10] = &(ar[0]); | 
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| 30 | float *pa00 = &(ar[0][0]); | 
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| 31 |  | 
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| 32 | static_assert((void*)&ar == (void*)&(ar[0] )); | 
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| 33 | static_assert((void*)&ar == (void*)&(ar[0][0])); | 
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| 34 |  | 
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| 35 | assert( (void *) pa == (void *) pa0 ); | 
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| 36 | assert( (void *) pa == (void *) pa00 ); | 
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| 37 |  | 
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| 38 | //      float (*b[3])[10]; | 
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| 39 | float *b[3]; | 
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| 40 | for (int i = 0; i < 3; i ++) { | 
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| 41 | b[i] = malloc(sizeof(float[10])); | 
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| 42 | } | 
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| 43 | ar[2][3]; | 
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| 44 | b[2][3]; | 
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| 45 | /* | 
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| 46 |  | 
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| 47 | */ | 
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| 48 |  | 
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| 49 | } | 
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| 50 |  | 
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| 51 | // Local Variables: // | 
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| 52 | // compile-command: "sed -f sedcmd bkgd-carray-mdim.c | gcc-11 -Wall -Wextra -x c -" // | 
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| 53 | // End: // | 
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