1, with a For loop can be used and array of cross-use, and some can be replaced, which is convenient to use which.
2, String m= "ABCD"; char []q=m.tochararray (); After this sentence can achieve 2 functions, (1): The string is coerced into an array, (2): The value of M, into a single character, once assigned to q[];
3, if the array is not assigned a value, then char is a space; string is null; Boolean is False;short, Long,double,int,,float is 0;
4, Exchange worthy words, must define an empty bottle; useful for sorting types;
5, for the loop inside the variable can change itself, not necessarily with the condition variable, do not limit the thinking, you define the variable n; then n++;
6, precision, shaping < character < floating point;
7,? "--": "--"; Trinocular operator to remember;
8, sum=sum+360; can be written, sum+=360;
First week of Java Foundation