FOR STATEMENT
for(expr1; expr2; expr3) statement;
Execute 'expr1' once. Then, while 'expr2' returns a non-zero value,
execute 'statement'. Every time 'statement' has been executed, or a 'continue'
statement has been executed, execute 'expr3' before next loop.
A 'break' in the 'statement' will terminate the loop. A 'continue' will
continue the execution from the beginning of the loop.
