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To build a generic swap in C, pass the size explicitly, create a temporary byte buffer, then use memcpy three times to rotate the bit patterns. VLA char buffer[size] is a GCC thing, for a more portable version malloc the temp and free it. Stanford CS107, lecture 4

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tetsuo

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45,838 views • 24 days ago •via X (Twitter)

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You cannot add to a void pointer in C. The compiler does not know the size. The everyday fix is to cast it to char* so the math is in bytes, then multiply by the element size yourself. Stanford CS107, lecture 4
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You cannot add to a void pointer in C. The compiler does not know the size. The everyday fix is to cast it to char* so the math is in bytes, then multiply by the element size yourself. Stanford CS107, lecture 4

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In C, `array[i]` does not add i to the address. It adds i times the size of one element. Assembly has to do that multiply. C hides it. Stanford CS107, lecture 9.
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This is a common C bug. You write a MAX macro, then call MAX(m++, n++). The preprocessor pastes the text, so it becomes (m++ > n++) ? m++ : n++. The smaller one increments once. The larger one increments twice. Stanford CS107, lecture 12
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This is a common C bug. You write a MAX macro, then call MAX(m++, n++). The preprocessor pastes the text, so it becomes (m++ > n++) ? m++ : n++. The smaller one increments once. The larger one increments twice. Stanford CS107, lecture 12

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