四则运算安卓

CreateExe.java
package com.example.cal;

public class CreateExp {
private char SignTemp, Sign[];
private double Num[], NumTemp;
private int STop, NTop;
private char cal[][];
String tempExp="";

public CreateExp() {
// TODO Auto-generated constructor stub
Sign = new char[100];
Num = new double[100];
cal = new char[100][100];
}

char Operator(int m) // 产生运算符
{
int a, b;
char oper = '1';
a = (int) (Math.random() * 5); // 产生随机整数用于除四取余后进行四种运算符号和四种数的选择
b = a = (int) (Math.random() * 2);
if (m == 2) // 无乘除法情况
{
switch (b) // 用于加减运算两种符选择
{
case 0:
oper = '+';
break;
case 1:
oper = '-';
break;
default:
break;
}
}
if (m == 1) // 有乘除法情况
{
switch (a) // 用于四则运算四种符号的选择
{
case 0:
oper = '+';
break;
case 1:
oper = '-';
break;
case 2:
oper = '*';
break;
case 3:
oper = '/';
break;
default:
break;
}
}
return oper;
}

void compute() // 计算
{
for(int i=0;i<=tempExp.length();i++){
Sign[i]=tempExp.charAt(i);
}
switch (Sign[STop - 1]) {
case '+':
Num[NTop - 2] += Num[NTop - 1];// 运算后将结果存入
STop--;
NTop--;
break;
case '-':
Num[NTop - 2] -= Num[NTop - 1];
STop--;
NTop--;
break;
case '*':
Num[NTop - 2] *= Num[NTop - 1];
STop--;
NTop--;
break;
case '/': // 判断除数是否为0,0的话结束
if (Num[STop - 1] == 0) {
return;
} else {
Num[NTop - 2] /= Num[NTop - 1];
STop--;
NTop--;
break;
} // 其中STop--;NTop--;实现的是将数据弹出栈
case ')':
STop = STop - 2;
break; // 发现')'对上个运算符进行判断
}
}

private int i, length;

public int getI() {
return i;
}

public void setI(int i) {
this.i = i;
}

public int getlength() {
return length;
}

public void setlength(int length) {
this.length = length;
}

double Run() // 运行函数
{
char temp;
int p = 0;
while (p <= length) // 读入数据
{
temp = cal[i][p];
if (temp >= '0' && temp <= '9') {
NumTemp = NumTemp * 10 + (double) (temp - 48);
} else {
Sign[STop] = SignTemp;
SignTemp = temp;
STop++; // 运算符入栈
if (Sign[STop - 1] != ')' && temp != '(') // 数字入栈
{
Num[NTop] = NumTemp;
NTop++;
NumTemp = 0;
}
switch (temp) // 进行有关运算优先级别的考虑
{
case '+':
case '-':
while (Sign[STop - 1] != '(' && STop - 1 > 0)
compute();
break; // "+""-"的时候考虑"("
case '*':
case '/':
while (Sign[STop - 1] != '(' && Sign[STop - 1] != '+'
&& Sign[STop - 1] != '-' && STop - 1 > 0)
compute();
break;
case '(':
break; // 继续读取
case ')':
while (Sign[STop - 1] != '(')
compute();
break;
default:
while (STop - 1 > 0)
compute();
break; // 结束
}
}
p++;
}
return Num[0];
}
public String getExp() {
int num1, num2, jishu, value = 100, m = 1, kuohao = 1, j, kuo;
char oper1;
String s_num1, s_num2, s_connect, t;
num1 = (int) (Math.random() * value) + 1;
num2 = (int) (Math.random() * value) + 1;
oper1 = Operator(m);
s_num1 = num1 + "";
s_num2 = num2 + "";
s_connect = s_num1 + oper1 + s_num2;
jishu = (int) (Math.random() * 4) + 2;
if (jishu > 2) // 对随机生成运算式里数值个数判断
{
for (j = jishu; j > 2; j--) // 两个数值以上运算式生成
{
s_num1 = s_connect;
oper1 = Operator(m);
num2 = (int) (Math.random() * value) + 1;
s_num2 = num2 + "";
if (kuohao == 1) // 随机产生括号
{
kuo = (int) (Math.random() * 2);
if (kuo == 0) {
s_num1 = '(' + s_num1 + ')';
}
}
kuo = (int) (Math.random() * 2);
if (kuo == 0) {
t = s_num1;
s_num1 = s_num2;
s_num2 = t;
}
s_connect = s_num1 + oper1 + s_num2;
}
tempExp=s_connect;
return s_connect;

}
return null;
}
}

Exp.java
package com.example.cal;

import android.util.Log;

public class Exp {// 产生表达式及结果
private int item_num = 0;// 0:两项，1：三项
private int sign_num = 0;// 0+,1-,2*,3/
private int sign_num_1 = 0;// 0+,1-,2*,3/ 三项的时候需要两个运算符
private int kuohao = 0;// 0不产生括号，1产生括号
private int kuohao_weizhi = 0;// 0表示前2项有括号，1表示后2项有括号

private int result;// 结果

private StringBuilder exp=new StringBuilder();// 式子

enum Sign {
add, subtract, multiply, divide
}

Exp() {
while(true){
if(createExp()==true)
{
break;
}
}
}

public StringBuilder getExp() {
return exp;
}

public void setExp(StringBuilder exp) {
this.exp = exp;
}

public void setResult(int result) {
this.result = result;
}

private boolean createExp() {
item_num = (int) (Math.random() * 2);
sign_num = (int) (Math.random() * 4);
int a = (int) (Math.random() * 100);// 随机生成0-100以内的数
int b = (int) (Math.random() * 100);
int c = (int) (Math.random() * 100);
kuohao = (int) (Math.random() * 2);
Log.e("jhd", item_num+"");
Log.e("jhd", sign_num+"");
Log.e("jhd", kuohao+"");
Log.e("jhd", a+"");
Log.e("jhd", b+"");
Log.e("jhd", c+"");
if (item_num == 0) {// 产生2项的情况
String temp = "";
switch (sign_num) {
case 0:// +
temp = a + "+" + b;
result = a + b;
break;
case 1:// -
temp = a + "-" + b;
result = a - b;
break;
case 2:// *
temp = a + "*" + b;
result = a * b;
break;
case 3:// /
temp = a + "÷" + b;
if (a % b != 0) {// 不整除旧返回false
return false;

}
result = a / b;
break;
}
exp.append(temp);
}
if (item_num == 1) {// 式子为三项时

sign_num_1 = (int) (Math.random() * 4);// 随机产生一个运算符
if (kuohao == 0) {// 不产生括号
// 比较优先级
String temp;
if (sign_num <= 1 && sign_num_1 > 1) {// 先计算后两项

if (calculate(b, sign_num_1, c) == null) {
return false;
}
result = calculate(a, sign_num, calculate(b, sign_num_1, c));
exp.append(a + getSign(sign_num) + b + getSign(sign_num_1)
+ c);
} else {// 计算前两项
if (calculate(a, sign_num, b) == null) {
return false;
}
if (calculate(calculate(a, sign_num, b), sign_num_1, c) == null) {
return false;
}
result = calculate(calculate(a, sign_num, b), sign_num_1, c);
exp.append(a + getSign(sign_num) + b + getSign(sign_num_1)
+ c);
}
}
else{
return false;
}
}

return true;

}

public Integer calculate(int a, int sign, int b) {
Integer temp = null;
switch (sign) {
case 0:
temp = a + b;

break;
case 1:
temp = a - b;
break;
case 2:
temp = a * b;
break;
case 3:
if (a % b != 0) {// 保证能整除
return null;
}
temp = a / b;
break;
}
return temp;
}

private String getSign(int sign) {
String temp = null;
switch (sign) {
case 0:
temp = "+";

break;
case 1:
temp = "-";

break;
case 2:
temp = "*";

break;
case 4:
temp = "/";

break;
}
return temp;
}

public int getResult() {// 得到产生表达式的结果
return result;
}

/*public String getExpression() {// 得到产生的表达式
//if(get)
}*/

}
ExpActivity.java
package com.example.cal;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class ExpActivity extends Activity implements OnClickListener {

private CreateExp expclass;
private TextView tv_exp;
private EditText et_result;
private Button next;
private Button exit;
private TextView all;
private TextView completed;
private TextView wrong;

private int index = 0;// 当前题目位置
private int wrong_num = 0;// 答错题目数量

private List<Exp> list;// 题目数组，所有题目

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_exp);
expclass = new CreateExp();// 随机产生一个2-3项四则运算式子，及式子的结果
// ---初始控件
intViews();

int num = getIntent().getIntExtra("num", 0);
if (num != 0) {
list = new ArrayList<Exp>();
for (int i = 0; i < num; i++) {
list.add(new Exp());
}
tv_exp.setText(list.get(index).getExp());//
all.setText("共计："+num);
completed.setText("已答："+(index));
wrong.setText("答错：");
}

}

private void intViews() {
// TODO Auto-generated method stub
tv_exp = (TextView) findViewById(R.id.tv_exp);
et_result = (EditText) findViewById(R.id.et_result);
next = (Button) findViewById(R.id.next_btn);
exit = (Button) findViewById(R.id.exit_btn);
all = (TextView) findViewById(R.id.all);
completed = (TextView) findViewById(R.id.completed);
wrong = (TextView) findViewById(R.id.wrong);

next.setOnClickListener(new OnClickListener() {// 点击下一题时，判断上一道是否正确，并且显示下一道

@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
if(et_result.getText().toString()==""){
Toast.makeText(getApplicationContext(), "答案不能为空！",
Toast.LENGTH_SHORT).show();
}
int result = Integer.valueOf(et_result.getText().toString());
if (index >= list.size()) {
Toast.makeText(getApplicationContext(), "题目已经答完！",
Toast.LENGTH_SHORT).show();
return;
}

if (result != list.get(index).getResult()) {
wrong_num++;
wrong.setText("答错："+wrong_num);
Log.d("jhd", "已答错数目：" + wrong_num);
}
index++;
completed.setText("已答："+(index));
if(index==list.size())
{
Toast.makeText(getApplicationContext(), "题目已经答完！",
Toast.LENGTH_SHORT).show();
return;
}

tv_exp.setText(list.get(index).getExp());
et_result.setText("");
}
});

exit.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
finish();
}
});
}

@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub

}

}
InputActivity.java
package com.example.cal;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class InputActivity extends Activity implements OnClickListener{

private EditText et_num;
private Button btn;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_input);
et_num=(EditText)findViewById(R.id.et_num);
btn=(Button)findViewById(R.id.num_btn);
btn.setOnClickListener(this);

}

@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
if(et_num!=null){
int n=Integer.valueOf(et_num.getText().toString());
Intent intent=new Intent(InputActivity.this,ExpActivity.class);
if(n==0){
Toast.makeText(getApplicationContext(), "请输入大于0的整数！", Toast.LENGTH_SHORT).show();
}
intent.putExtra("num", n);
startActivity(intent);
}
}


}
MainActivity.java
package com.example.cal;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity implements OnClickListener {

private Button enterBtn;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
enterBtn=(Button)findViewById(R.id.enter_btn);
enterBtn.setOnClickListener(this);
}
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
Intent intent=new Intent(MainActivity.this,InputActivity.class);
startActivity(intent);
}


}

介绍：

随机产生最多三位数，随机产生运算符，用户可选择出题数目，系统随机产生算式，用户回答，系统可判断正误。

小伙伴的地址在这里：http://www.cnblogs.com/wuyw/