Mission requirements: the use of C or Java language to automatically generate a complete four arithmetic questions of procedure. The basic software functions are as follows.

(1) automatically generates four arithmetic operation of Equation 2 number less than 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

Number (3) title can be customized

(4) parameters can be controlled

Whether to include multiplication and division

Controllable range values of the operands (e.g., operands within 100 or within 1000)

Whether operands containing negative　　　　

(5) generating operation to an external file title stored in result.txt

A. Requirements Analysis

　　In response to master degree students familiar practice for four operations, reduce the burden Setters, so design a program can automatically write the four operations in the title.

II. Functional Design

basic skills
- Automatically generating a count of formula
- Randomly generated symbols arithmetic formula
extensions

An arithmetic formula to generate automatically calculated and the arithmetic answers given
Arithmetic equation can be controlled if there is negative
Arithmetic formula can control whether or not there is an expression, multiplication and division
Finally, the results generated will be saved for easy viewing in result.txt file
Arithmetic formula can control its operating range

III. Design and Implementation

　　C language
　　Quote <stdio.h> library
　　Quote <time.h> Library
　　Quote <stdlib.h> library
　　And then multiplied by 2 minus the calculated negative value itself stars
　　fopen function to store an output value

IV. Test Run

　　In the console inside the test run results and performance in the output text inside

V. snippet

　　rand () to generate random values, use it to obtain the value of n, can be calculated and assigned corresponding to the following formula op.

    for(a=0;a<size;a++)
            {
            i=rand()%z+1;
            j=rand()%z+1;
            n=rand()%4;
            if(n==0){op='+'; q=i+j;}
            if(n==1){op='-'; q=i-j;}
            if(n==2){op='*'; q=i*j;}
            if(n==3){op='/'; q=i/j;}
            printf("%d%c%d=%d\n",i,op,j,q);    
            fprintf(fp,"%d%c%d=%d\n",i,op,j,q);
            }

　　If you want to generate negative then the upper limit is multiplied by 2 and then subtract itself is the answer you want.

                i=rand()%(2*z)-z+1;
                j=rand()%(2*z)-z+1;
                n=rand()%2;
                if(n==0){op='+'; q=i+j;}
                if(n==1){op='-'; q=i-j;}

VI. Summary

　　Write your own if the judge sentences a little more, and I wrote the comment caused by bad habits sometimes I just could not understand what they write, but after this first experience and training, I believe that next time I will be able to based on the original do better.

Seven. PSP

PSP	SUMMARY	Plan time (min) required to complete a total of	The actual time required for completion (min)
Planning	plan	8	6
Estimate	It estimated that the task requires much time and planning generally work steps	8	6
Development	Develop	66	64
Analysis	Needs analysis (including learning new technologies)	6	10
Design	Specific design	10	12
Coding	Specific coding	40	30
Test	Test (self-test, modify the code, submit modifications)	10	12
Reporting	report	3	3
Postmortem & Process Improvement Plan	Later summarized, and process improvement plan	3	3

Caiqi Hong software engineering job a second time - the four operations