标签：efault math 程序 错误 技术分享 ++ tin jpg 评价
将中缀表达式转换为后缀表达式并对后缀表达式进行计算
import java.util.Stack;
import java.util.regex.Pattern;
public class StringToArithmetic {
public StringToArithmetic() {
}
// 将中缀表达式字符串计算得到结果
public static double stringToArithmetic(String string) {
return suffixToArithmetic(infixToSuffix(string));
}
// 将中缀表达式转换为后缀表达式
public static String infixToSuffix(String exp) {
Stack<Character> s = new Stack<Character>();
// 要输出的后缀表达式字符串
String suffix = "";
int length = exp.length(); // 输入的中缀表达式的长度
for (int i = 0; i < length; i++) {
char temp;
char ch = exp.charAt(i);
switch (ch) {
case ‘ ‘:
break;
case ‘(‘:
s.push(ch);
break;
case ‘+‘:
case ‘-‘:
while (s.size() != 0) {
temp = s.pop();
if (temp == ‘(‘) {
s.push(‘(‘);
break;
}
suffix += temp;
}
s.push(ch);
break;
case ‘ב:
case ‘÷‘:
while (s.size() != 0) {
temp = s.pop();
if (temp == ‘+‘ || temp == ‘-‘ || temp == ‘(‘) {
s.push(temp);
break;
} else {
suffix += temp;
}
}
s.push(ch);
break;
case ‘)‘:
while (!s.isEmpty()) {
temp = s.pop();
if (temp == ‘(‘) {
break;
} else {
suffix += temp;
}
}
break;
default:
suffix += ch;
break;
}
}
while (s.size() != 0) {
suffix += s.pop();
}
return suffix;
}
public static double suffixToArithmetic(String exp) {
Pattern pattern = Pattern.compile("\\d+||(\\d+\\.\\d+)");
String[] strings = exp.split("");
Stack<Double> stack = new Stack<Double>();
for (int i = 0; i < strings.length; i++) {
if (strings[i].equals("")) {
continue;
}
if (pattern.matcher(strings[i]).matches()) {
stack.push(Double.parseDouble(strings[i]));
}
else {
double y = stack.pop();
double x = stack.pop();
stack.push(calculate(x, y, strings[i]));
}
}
return stack.pop();
}
private static Double calculate(double x, double y, String string) {
// TODO Auto-generated method stub
if (string.trim().equals("+")) {
return x + y;
}
if (string.trim().equals("-")) {
return x - y;
}
if (string.trim().equals("×")) {
return x * y;
}
if (string.trim().equals("÷")) {
return x / y;
}
return (double) 0;
}创建题目类
public class createquestions {
public static String create(int level){
String add = "+", sub = "-", multi = "×", div = "÷";
String result="";
int r1=(int)(Math.random()*9+1);
int r2=(int)(Math.random()*9+1);
int r3=(int)(Math.random()*9+1);
//三个整数
int fenzi1=(int)(Math.random()*9+1);
int fenmu1=(int)(Math.random()*9+1);
String fenshu1=fenzi1+"/"+fenmu1;
int fenzi2=(int)(Math.random()*9+1);
int fenmu2=(int)(Math.random()*9+1);
String fenshu2=fenzi2+"/"+fenmu2;
int fenzi3=(int)(Math.random()*9+1);
int fenmu3=(int)(Math.random()*9+1);
String fenshu3=fenzi3+"/"+fenmu3;
//三个分数
int suiji1=(int)(Math.random()*4);
//第一个运算符
int suiji11=(int)(Math.random()*3);
//生成括号
int suiji2=(int)(Math.random()*4);
//第二个运算符
if (level>=1) {
if(suiji11==0&&level==2&&suiji1!=0&&suiji1!=1)
result+="(";
if (level==3)
result+=fenshu1;
else
result+=r1;
if (suiji1 == 0)
result+=add;
if (suiji1 == 1)
result+=sub;
if (suiji1==2)
result+=multi;
if(suiji1==3)
result+=div;
if(suiji11==1&&level==2&&suiji2!=0&&suiji2!=1)
result+="(";
if (level==3)
result+=fenshu2;
else
result+=r2;
if(suiji11==0&&level==2&&suiji1!=0&&suiji1!=1)
result+=")";
}
if (level>=2){
if (suiji2==0)
result+=add;
if (suiji2 == 1)
result+=sub;
if (suiji2==2)
result+=multi;
if(suiji2==3)
result+=div;
if (level==3)
result+=fenshu3;
else
result+=r3;
if(suiji11==1&&suiji2!=0&&suiji2!=1)
result+=")";
}
return result;
}main类
import java.util.Scanner;
public class calculate {
public static void main(String[] args) {
System.out.println("输入你要生成的题数");
Scanner scan = new Scanner(System.in);
int tishu = scan.nextInt();
System.out.println("输入你要生成题目的等级(输入1或2或3)");
int dengji = scan.nextInt();
//调用一个循环
double answer;
int zhengquelv = 0;
double[] daan = new double[tishu];
switch (dengji) {
case 1:
for (int i = 0; i < tishu; i++) {
String a = createquestions.create(1);
String b = a + "=";
System.out.print(b);
answer = scan.nextDouble();
daan[i] = StringToArithmetic.stringToArithmetic(a);
if (answer == daan[i])
zhengquelv++;
}break;
case 2:
for (int i = 0; i < tishu; i++) {
String a = createquestions.create(2);
String b = a + "=";
System.out.print(b);
answer = scan.nextInt();
daan[i] = StringToArithmetic.stringToArithmetic(a);
if (answer == daan[i])
zhengquelv++;
}break;
case 3:
for (int i = 0; i < tishu; i++) {
String a = createquestions.create(3);
String b = a + "=";
System.out.print(b);
answer = scan.nextInt();
daan[i] = StringToArithmetic.stringToArithmetic(a);
if (answer == daan[i])
zhengquelv++;
}break;
}
if(dengji<1||dengji>3)
System.out.println("题目等级输入错误");
if (dengji >= 1&&dengji <= 3) {
System.out.println("答案为");
for (
double daanwei : daan)
System.out.print(daanwei + " ");
System.out.println("正确率为" + zhengquelv + "/" + tishu);
}
}
}关于判断题目的正确率出现了一些小问题
经过组内商讨，得出了解决办法
对中缀转后缀和后缀的计算类的编写
20172315胡智韬30%
20172312彭霖30%
20172318陆大岳40%
20172315『Java程序设计』课程 结对编程练习_四则运算第二周阶段总结
标签：efault math 程序 错误 技术分享 ++ tin jpg 评价
原文地址：https://www.cnblogs.com/huzhitao/p/9011407.html
