20194638 automatically generates four arithmetic problem first edition report

demand analysis

     In order to facilitate the students to improve computational abilities, and the parents do not pay too much time and effort to solve this problem through this program.

The basic functions of
     an automatic four arithmetic formula to generate two operands within 10 100 (+ - * /), operation results are required within 100

     2, discarding duplicates equation. = 2 + 3 + 3 = 2 and Equation 2 is repeated and 3 + = 3 + 2 = not repeated formula

     3, the number of items can be customized

     4, the control parameters may contain multiplication and division, the number of controllable operation range of values ​​(e.g., less than 100 or operand within 1000), whether or not containing a negative operand　　　

     5, the generated file to an external memory operation problems in result.txt

feature design

1.import.Java.until*；

2.输入：Scanner reader=new Scanner(System.in);

Math class methods Radom of: generating a random number 3.

4.for the circulation and use if else

Test shots.

 

code segment

Using random numbers

int a = (int) (Math.random() * 100);
int b = (int) (Math.random() * 100);

　　Operational control

System.out.println ( "Please select operation within 100 or within the operation 1000"); 
 Nl = sc.nextInt () 
System.out.println ( "Please enter the number of questions to be produced"); 
N2 of sc.nextInt = () 
System.out.println ( "input 1 comprising multiplication and division, excluding 0"); 
 N3 = sc.nextInt (); 
System.out.println ( "not containing a negative input, comprising negative 0"); 
 N4 = sc.nextInt ();

　　Switch control operation

switch (b) {
  case 0:
	        r=m1+m2;
	        break;
case 1:
	        r=m1-m2;
	        break;
case 2:
	        r=m1*m2;
	        break;
case 3:
	        r=m1/m2;		
	        break;
default:
	        break;
	        	}

　　to sum up

The use of java is not very skilled, especially the use of recycled order, and I am not very neat when playing program, conditioning is not very clear, so it should be positive to practice.

PSP

PSP	SUMMARY	Plan time required to complete a total of	Time required to achieve complete
planning	Program content	15	10
Estimate	Design steps	20	15
Develomopment	Developing content	70	90
Anailsis	demand analysis	20	10
Design	Specific design	90	90
Coding	test	50	60
Test	report	20	10
Reporting	to sum up	10	5