Code Debug Test on arithmetic

1. First Test whether the problem can be negative, 0?

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Summary: The number of questions to 0, and did not prompt re-input, but output blank, and when the output problem is negative when the system prompts the error, and the prompt to terminate

2. The detection operation is worth the range:

Summary: When the operand range is negative, the system does not prompt an error, but the range is the absolute value of the negative, and when the range is set to 0, the system prompts to stop working

3. What happens when I enter an unexpected character (y/n)?

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Summary: When entering letters or numbers, the system error, output space, and no op-type output

4. When the number of expressions and the interval input letters or numbers when the system has no error?

Summary: When the number of expressions entered into the alphabet, the system aborts, and when each line of the interval of the expression of the letter, the system continues to output no stop, Error!

Code Debug Test on arithmetic