For loop application: Iterative method and Exhaustive method

for () loop.
Four elements: initial conditions, cyclic condition, state change, circulation body.
Execution process: Initial conditions--cyclic condition--cyclic body--state change--cycle condition ....
Note: For parentheses are separated by semicolons, do not add semicolons after the parentheses.
Nested for.
Application: Iterative method, poor lifting method.
First, iterative method: There are certain rules.
Each cycle is obtained from the results of the last operation, the result of this operation is to prepare for the next operation.

Second, the poor lifting method:
Use the loop to go through all the possible situations, and then use the IF condition to filter out the results satisfying the requirements.

For loop application: Iterative method and Exhaustive method