12, distinguish three cycles, the cycle of death

12.1 three loop differences

Three kinds of differences cycle:

　　1. If the conditional never been satisfied, then the for loop and while loop will be executed zero times, but do-while loop will execute at least once.

　　Variable 2.for circulating in parentheses among definition, only the inner loop can be used. while loop and do-

while initialization statements already outside, so came out cycle can continue to use.

 

Can be nested between cycles

 

12.2 infinite loop

Never not stop the cycle, called an infinite loop