30 lines
929 B
C
30 lines
929 B
C
#include <stdio.h>
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typedef int Length;
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#define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
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void test() {
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// struct point p1; // COMPILER ERROR: unknown storage size because struct not declared in this scope
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struct point *p1; // works because it's a forward declaration for an opaque pointer, and incomplete type, but cannot do pointer arithmetic
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printf("struct pointer size: %d\n", sizeof(struct point *));
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printf("int * size: %d\n", sizeof(int *));
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printf("char * size: %d\n", sizeof(char *));
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}
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int main(int argc, char *argv[]) {
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// you can declare the struct template along with a declaration and definition of a variable,
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// and then you can still reuse the struct template again later, however, probably not in another function or file scope
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struct point {
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int x;
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int y;
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} p = {100, 100};
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struct point another_point = {0, 3};
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printf("struct size: %d\n", sizeof(struct point));
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test();
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}
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