I follow the execution process of this small program: first, I take exp and "\ +" as parameters, call the calculation (String, String) method in the AbstractCalculator class, call split () of the same kind in the calculation (String, String), then call the calculation (int, int) method, enter the subclass from this method, after executing return num1 + num2, return the value to the AbstractCalculator class, assign it to result, and print it out. This just verifies our thinking at the beginning.如今楚军时日如虹，势头正猛，交战败的会是自己。When "cracking" the sand pile paradox, we often have to set a fixed boundary. If we say "10,000 grains of sand are a pile of sand", then less than 10,000 grains of sand cannot be called a pile of sand. Then it is somewhat unreasonable to distinguish 9999 grains of sand from 10001 grains of sand. This has to set a variable boundary, but what is this boundary? We don't know now. Then the value of "10,000 grains of sand are a pile of sand" originally set as knowledge will be reduced.当即笑道：愿闻其详，多谢了。On October 18, the General Office of the State Administration of Press, Publication, Radio, Film and Television issued a report on the investigation and punishment of false reports published by the media, which reported on the investigation and punishment of false reports published by Nanhu Evening News:1. The borrower is required to repay the principal and interest on a monthly basis. In this way, the amount to be repaid each month is very small and the repayment pressure is also small. The lender can receive the repayment on a monthly basis with little risk. 2. Credit audit introduces socialization factors. That is, the borrower's ID card, account book, marriage certificate, academic certificate, etc. can all increase personal credit scores, but these data do not need to be provided with the original, and their authenticity is difficult to be effectively guaranteed. Therefore, the auction believes that the online community and users' online circle of friends are also one of the important parts of their credit rating system. The more friends and members' friends in the inner circle of the website, the higher the number of times individuals borrow and lend, and the higher the credit rating. In this way, the network activity and the user's personal identity, financial ability, bank credit, etc. together form a complete set of evaluation system. The unsecured and unsecured mode has only credit requirements for the borrower but no mortgage, and does not assume guarantee responsibility for the lender. The lender and the borrower trade on their own, and the auction only exists as a witness and trading platform. Therefore, in fact, this form is relatively risky for lenders. However, the winning interest rate for auction is often above 15%, which is still a great temptation for lenders. Therefore, investment in auction and loan has higher risks and higher returns. Because the transaction is concluded in the form of competitive bidding and both parties to the transaction are free to trade, the auction and loan belong to pure intermediary P2P. The auction will blacklist the borrower who fails to repay the loan within the time limit and make it public, but it will not compensate the lender for the economic losses. The auction will only refund the lender's handling fee, so the potential risks of fund recovery can only be borne by the lender itself.同时也是一头雾水，想着到底是什么地方出现了问题。
