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In this noncompliant code example pointer subtraction is used to determine how many free elements are left in the nums array.
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int nums[SIZE]; char *strings[SIZE]; int *next_num_ptr = nums; int free_bytes; /* increment next_num_ptr as array fills */ free_bytes = strings - (char **)next_num_ptr; |
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In this compliant solution, the number of free elements is kept as a counter and adjusted on every array operation. It is also calculated in terms of free elements instead of bytes. This prevents further mathematical errors.
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int nums[SIZE]; char *strings[SIZE]; int *next_num_ptr = nums; int free_bytes; /* increment next_num_ptr as array fills */ free_bytes = (&(nums[SIZE]) - next_num_ptr) * sizeof(int); |
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