This simple class includes two methods: perimeter (int length, int width) and area (int length, int width). In the first method, calling two parameters roughly means the length and width of the rectangle, which returns 2* (length+width); There is something wrong with the statement. I copied my paragraph to calculate the perimeter of this rectangle and return it. The second method is to calculate the area of the rectangle and return it.

Statement "perimeter ="+rectangle. Perimeter (5 5,4) can be divided into three parts: (1) "perimeter =" means that a String is a string object in java; (2) "+"is a connection symbol, and strings in java can be connected by+. For example, if you want to output the string "hello world", you can use the statement system. out . print in(" Hello World ")； But you can also use the system. Out.printin ("hello"+"world ") or system. out . printin(" he "+" llo world ")； (3) Rectangle. perimeter (5,4) is a calling class method, which will give you an integer return value, so this expression becomes: "string"+integer value; In java, this situation will first program the plastic string and then append it to the string. For example, the above method returns the number 5, so the expression is:

"perimeter ="+5, and the final output is perimeter=5. Okay, I tried.