First, whether the test question is repeated:
In the program, I was divided into 6 modules, I only in the "Simple plus minus" module to avoid duplication of the problem, the other modules are also implemented in a similar way, it is not reflected in the program.
In the Add and subtract module, if the maximum value of the operation is 30, the number of questions is 1000, after running the program found no repetition; if the maximum value of the operation is 10, and the number of questions is 300, the program is no longer down, the reason is 0-10 of these 11 numbers can only out 11*11*2=242 problem, If there are 300, there will be duplicates, and the program has been implemented to avoid duplication, so the program run error.
In other modules, regardless of the maximum value, can output any number of arithmetic problems, but it can be found that when the number of questions are few, the topic is almost no repetition, the number of issues, there will be a lot of repetition!
Second, test the boundary value:
The main test question number, because in the realization avoids duplicates, uses the string array, when the question number is 0 o'clock, will have the array out of bounds error, but when the question number Tens, 100,000, million, the question Time will become, affects the performance!
Arithmetic Small program test