Why is the default of switch followed by break?

At first, many people thought it was 5 In fact, the result is 7.

reason ： because switch Meet again The matching condition is that it will always be executed downward by default , So in matching default The condition in will be executed downward case 1 and case 2 Conditions in .

As shown in the figure below default After matching, the following two conditions will be executed, resulting in b=4.

  And in the case 1: Add break And then it's like this , It's only going to be executed once b++, As shown in the figure below .

And in the defaul Followed by break after b It's not going to happen ++ 了 , As shown in the figure below .

 

If the foundation is not strong, the earth will shake and the mountains will shake ！