进一步了解重复控制指令、串操作指令及重复前缀的格式和功能，通过解决循环问题练习这些指令和重复前缀的选用。对于既可以用重复控制指令，又可以用串操作指令及重复前缀的场合，比较两者的优劣。

练习针对具体问题建立合适的循环结构，进一步了解计数控制、条件控制的循环结构的适用场合。

-A better understanding of repetitive control instructions, operating instructions and repeat string prefix format and features, by addressing the issue of training cycle to repeat these instructions and the choice of prefix. Both can be used for repetitive control commands, but also can be used string and repeat the operation command prefix occasions to compare the merits and demerits of both. Issue-specific exercises to establish the right circle structure, a better understanding of counting control, the conditions of the control structure of the application of the cycle of occasions.