Day 7 small exercise

1. Calculation n The factorial

2. Calculation 1！+2！...+10！

2.1  The first method （ Write directly in the loop body ）

2.2  The second method （ Double cycle ）

3. Find the corresponding number in an array

4. Find an element in an ordered array by dichotomy

4.1（ His writing ）

4.2（ course ）

5. Characters converge from two sides to the middle

6. The login password