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copied!<p>Checked the generated IL and it gives out different results;</p> <p>The correct swap generates a straightforward:</p> <pre><code>IL_0001: ldc.i4.s 25 IL_0003: stloc.0 //create a integer variable 25 at position 0 IL_0004: ldc.i4.s 36 IL_0006: stloc.1 //create a integer variable 36 at position 1 IL_0007: ldloc.1 //push variable at position 1 [36] IL_0008: ldloc.0 //push variable at position 0 [25] IL_0009: xor IL_000a: stloc.1 //store result in location 1 [61] IL_000b: ldloc.0 //push 25 IL_000c: ldloc.1 //push 61 IL_000d: xor IL_000e: stloc.0 //store result in location 0 [36] IL_000f: ldloc.1 //push 61 IL_0010: ldloc.0 //push 36 IL_0011: xor IL_0012: stloc.1 //store result in location 1 [25] </code></pre> <p>The incorrect swap generates this code:</p> <pre><code>IL_0001: ldc.i4.s 25 IL_0003: stloc.0 //create a integer variable 25 at position 0 IL_0004: ldc.i4.s 36 IL_0006: stloc.1 //create a integer variable 36 at position 1 IL_0007: ldloc.1 //push 36 on stack (stack is 36) IL_0008: ldloc.0 //push 25 on stack (stack is 36-25) IL_0009: ldloc.1 //push 36 on stack (stack is 36-25-36) IL_000a: ldloc.0 //push 25 on stack (stack is 36-25-36-25) IL_000b: xor //stack is 36-25-61 IL_000c: dup //stack is 36-25-61-61 IL_000d: stloc.1 //store 61 into position 1, stack is 36-25-61 IL_000e: xor //stack is 36-36 IL_000f: dup //stack is 36-36-36 IL_0010: stloc.0 //store 36 into positon 0, stack is 36-36 IL_0011: xor //stack is 0, as the original 36 (instead of the new 61) is xor-ed) IL_0012: stloc.1 //store 0 into position 1 </code></pre> <p>It's evident that the code generated in the second method is incorect, as the old value of j is used in a calculation where the new value is required.</p>

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