c / intermediate
Snippet
Efficient Data Packing with Bit Fields
Bit fields allow defining structure members with a specific number of bits to save memory or map to hardware registers.
snippet.c
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#include <stdio.h>struct FilePermissions {unsigned int read : 1;unsigned int write : 1;unsigned int execute : 1;unsigned int owner_id : 5;};int main() {struct FilePermissions p = {1, 0, 1, 15};printf("Size: %zu bytes\n", sizeof(p));if (p.read) printf("Read access granted.\n");return 0;}
Breakdown
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unsigned int read : 1;
Allocates exactly 1 bit for the 'read' member.
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unsigned int owner_id : 5;
Allocates 5 bits, allowing values from 0 to 31.