先把两个合成一个,然后各取各的
数字型:
a=a+b
b=a-b;
a=b-a;
字符型:
a=a+b;
b=a.substring(0,a.length()-b.length());
a=a.substring(b.length());
数字型:
a=a+b
b=a-b;
a=b-a;
字符型:
a=a+b;
b=a.substring(0,a.length()-b.length());
a=a.substring(b.length());
调试欢乐多
a=a+b
b=a-b;
a=a-b;
a=100;b=210;a=a+b;//a(310)
b=a-b;//b(100)
a=a-b;//a(210)OK!