86 lines
1.8 KiB
C
86 lines
1.8 KiB
C
void test1() {
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int a = 3;
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int* pb = &a;
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int c = *pb;
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printf("Reading from a pointer: %d %d\n", a, c);
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*pb = 4;
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printf("Writing to a pointer: %d\n", a);
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printf("Testing casts: %d %g %g %d\n", 3, (float) 3, 4.5, (int) 4.5);
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}
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void test2() {
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int x = 4;
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int px = &x;
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// int z = * px; // An error, expected a pointer type
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int y = * (int*) px;
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printf("Testing reading (int*): %d\n", y);
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}
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void test3() {
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int px = (int) malloc(120);
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* (int*) px = 8;
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* (int*) (px + 4) = 9;
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printf("Testing writing (int*): %d %d\n", * (int*) px, * (int*) (px + 4));
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free((void*) px);
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}
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void test4() {
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int x = 0x12345678;
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int px = &x;
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int a = * (char*) px;
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int b = * (char*) (px + 1);
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int c = * (char*) (px + 2);
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int d = * (char*) (px + 3);
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printf("Testing reading (char*): 0x%02x 0x%02x 0x%02x 0x%02x\n", a, b, c, d);
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}
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void test5() {
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int x = 0xFFFFFFFF;
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int px = &x;
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* (char*) px = 0x21;
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* (char*) (px + 1) = 0x43;
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* (char*) (px + 2) = 0x65;
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* (char*) (px + 3) = 0x87;
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printf("Testing writing (char*): 0x%08x\n", x);
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}
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int f(int b) {
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printf("f(%d)\n", b);
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return 7 * b;
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}
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void test6() {
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int fp = &f;
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int x = (*(int(*)()) fp)(10);
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printf("Function pointer result: %d\n", x);
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}
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void test7() {
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int px = (int) malloc(120);
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* (float*) px = 8.8f;
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* (float*) (px + 4) = 9.9f;
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printf("Testing read/write (float*): %g %g\n", * (float*) px, * (float*) (px + 4));
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free((void*) px);
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}
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void test8() {
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int px = (int) malloc(120);
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* (double*) px = 8.8;
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* (double*) (px + 8) = 9.9;
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printf("Testing read/write (double*): %g %g\n", * (double*) px, * (double*) (px + 8));
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free((void*) px);
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}
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int main() {
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test1();
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test2();
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test3();
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test4();
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test5();
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test6();
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test7();
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test8();
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return 0;
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}
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