Instruction in memory has two parts: opcode and operands. The operands are subjects of the operation, such as data values, registers, or memory addresses. Due to variety of opcodes and operands, instructions may occupy different sizes of bytes in memory
Answer: You need a temporary variable to hold the value 3
Explanation:
So, aList[0] is 3 and aList[1] is 19, if it will be as it is you litteraly say to the compiler to change aList[0] to aList[1] at this moment aList[0] is 19 and aList[1] also is 19 and if you try to change aList[1] to aList[0] it will not change its value because they are the same.
You need temp variable to keep one of the values.