计算器（带括号，可用负号）

[{"title":"（ 12 个子文件 29KB ） 计算器（带括号，可用负号）","children":[{"title":"calculator","children":[{"title":".project <span style='color:#111;'> 386B </span>","children":null,"spread":false},{"title":"calculator1.java <span style='color:#111;'> 7.93KB </span>","children":null,"spread":false},{"title":"calculator1.class <span style='color:#111;'> 7.12KB </span>","children":null,"spread":false},{"title":"Window.java <span style='color:#111;'> 189B </span>","children":null,"spread":false},{"title":"help","children":[{"title":"计算器.doc <span style='color:#111;'> 38.50KB </span>","children":null,"spread":false},{"title":"help.txt <span style='color:#111;'> 604B </span>","children":null,"spread":false}],"spread":true},{"title":"jisuan.java <span style='color:#111;'> 2.57KB </span>","children":null,"spread":false},{"title":"IntegerException.java <span style='color:#111;'> 223B </span>","children":null,"spread":false},{"title":"IntegerException.class <span style='color:#111;'> 455B </span>","children":null,"spread":false},{"title":"Window.class <span style='color:#111;'> 473B </span>","children":null,"spread":false},{"title":"jisuan.class <span style='color:#111;'> 2.31KB </span>","children":null,"spread":false},{"title":".classpath <span style='color:#111;'> 226B </span>","children":null,"spread":false}],"spread":false}],"spread":true}]