四则运算 第二阶段

自动生成题目

要求：题目避免重复

           可定制

源代码

import java.util.Random;
import java.util.Scanner;

public class fun {
public int len1;//打印个数
public int len2;//操作数个数
public int multi;//乘除法
public int paren;//括号
public int leftR;//最小值
public int rightR;//最大值
public int leftP;//左括号
public int rightP;//右括号
public int index;//记录重复生成次数是否过多
double[] a;//存储操作数
int[] b;//存储操作符
String[] jiLu;//记录出现过的题目
double[] result;//记录答案
int[] fault;//记录错题下标
int id;

public fun() {
}

public fun(int i1, int i2, int i3, int i4, int i5, int i6) {
this.len1 = i1;
this.len2 = i2;
this.multi = i3;
this.paren = i4;
this.leftR = i5;
this.rightR = i6;
a = new double[len2];//存储操作数
b = new int[len2 - 1];//存储操作符
jiLu = new String[len1];//记录出现过的题目
result = new double[len1];
fault = new int[len1 + 1];
id = 0;
}

public void ff() {

int index = 0;
if (this.multi == 1) {
this.multi = 4;
} else {
this.multi = 2;
}

Random random = new Random();

int i = 0;
if (this.paren == 1) {
this.paren = len1;
}

while (i < len1) {
jiLu[i] = "";
String str = "";
for (int j = 0; j < len2 - 1; j++) {//生成操作符
b[j] = random.nextInt(this.multi);
jiLu[i] += b[j];
}

for (int j = 0; j < len2; j++) {//生成操作数
//System.out.println(j);
a[j] = random.nextInt(this.rightR - this.leftR + 1) + this.leftR;
if (j > 0) {
while (b[j - 1] == 3 && a[j] == 0) {
//System.out.println("----");
a[j] = random.nextInt(this.rightR - this.leftR + 1) + this.leftR;
}
}
jiLu[i] += a[j];
}

if (this.paren != 0) {
//0+0+0=
this.leftP = random.nextInt(len2 - 1);//左括号能存在的位置
jiLu[i] += this.leftP;
this.rightP = random.nextInt(len2 - this.leftP - 1) + this.leftP + 1;//右括号位置
jiLu[i] += this.rightP;
}

int flag = f3(i);//计算是否重复
jiLu[i] = "";
if (flag == 0) {
int iFlag = 0;
for (int j = 0; j < len2; j++) {
if (this.paren >= 1 && this.leftP == j) {
System.out.print("(");
jiLu[i] += "(";
}
System.out.print((int) a[j]);
jiLu[i] += (int) a[j];
if (this.paren >= 1 && this.rightP == j) {
System.out.print(")");
jiLu[i] += ")";
this.paren--;
}
if (iFlag != len2 - 1) {
System.out.print(this.f2(b[j]));
jiLu[i] += this.f2(b[j]);
}
iFlag++;
}
System.out.print("=");
jiLu[i] += "=";
f4(i);
if (f5(i) == 0) {
this.fault[this.id] = i;
this.setId();
index++;
}
i++;
}
}
System.out.print("错题率为：");
double rate = index / len1;
rate *= 100;
System.out.println(String.format("%.2f", rate) + "%");
}

public void setId() {
this.id++;
}

public int f3(int i) {
if (this.index >= len1 * len1) {
i = len1;
System.out.println("重复生成次数过多，程序自动结束，请检查操作数个数与生成题目之间是否合法");
}

for (int j = 1; j < i; j++) {
if (jiLu[j].equals(jiLu[i])) {
this.index++;
return 1;
}
}
return 0;
}

public String f2(int i) {
if (i == 0) {
return "+";
} else if (i == 1) {
return "-";
} else if (i == 2) {
return "*";
} else {
return "/";
}
}

public double f4(int t) {
double dR = 0.0;
if (this.paren == 0) {//没有括号
for (int j = 0; j < len2 - 1; j++) {
if (this.b[j] == 1) {
a[j + 1] = -a[j + 1];
}
if (this.b[j] == 2) {
dR = a[j] * a[j + 1];
a[j] = 0;
a[j + 1] = dR;
}
if (this.b[j] == 3) {
dR = a[j] / a[j + 1];
a[j] = 0;
a[j + 1] = dR;
}
}

result[t] = 0.0;
for (int j = 0; j < len2; j++) {
result[t] += a[j];
}
} else {
//System.out.println("-----");
for (int i = this.leftP; i < this.rightP; i++) {//计算括号内
if (this.b[i] == 1) {
a[i + 1] = -a[i + 1];
}
if (this.b[i] == 2) {
dR = a[i] * a[i + 1];
a[i] = 0.0;
a[i + 1] = dR;
}
if (this.b[i] == 3) {
dR = a[i] / a[i + 1];
a[i] = 0;
a[i + 1] = dR;
}
}
dR = 0.0;
for (int j = this.leftP; j < this.rightP + 1; j++) {
dR += a[j];
}
a[this.leftP] = dR;//括号内计算结果

double[] temp = new double[len2 - (this.rightP - this.leftP)];//存去掉括号后的操作数
int[] tempB = new int[len2 - (this.rightP - this.leftP) - 1];//存括号外的操作符

temp[this.leftP] = dR;
if (this.rightP != len2 - 1) {
tempB[this.leftP] = b[this.rightP];
}

for (int i = 0; i < this.leftP; i++) {
temp[i] = a[i];
tempB[i] = b[i];
}
for (int i = this.rightP + 1, index = this.leftP + 1; i < len2; i++, index++) {
temp[index] = a[i];
}
for (int i = this.rightP + 1, index = this.leftP + 1; i < len2 - 1; i++, index++) {
tempB[index] = b[i];
}

for (int j = 0; j < len2 - (this.rightP - this.leftP) - 1; j++) {
if (tempB[j] == 1) {
temp[j + 1] = -temp[j + 1];
}
if (tempB[j] == 2) {
dR = temp[j] * temp[j + 1];
temp[j] = 0;
temp[j + 1] = dR;
}
if (tempB[j] == 3) {
dR = temp[j] / temp[j + 1];
temp[j] = 0;
temp[j + 1] = dR;
}
}

result[t] = 0.0;
for (int j = 0; j < len2 - (this.rightP - this.leftP); j++) {
result[t] += temp[j];
}
}
return result[t];
}

public int f5(int i) {
Scanner sc = new Scanner(System.in);
double d = sc.nextDouble();
if ((d - result[i] <= 0.01) && (d - result[i] >= -0.01)) {
System.out.println("回答正确");
return 1;
} else {
System.out.print("计算错误，正确答案为:");
System.out.println(String.format("%.2f", result[i]));
return 0;
}
}

public void f6() {
for (int i = 0; i < this.id; i++) {
if (this.fault[i] != -1) {
System.out.print(jiLu[this.fault[i]]);
if (f5(this.fault[i]) == 1) {
this.fault[i] = -1;
}
}
}
for (int i = 0; i < this.id; i++) {
if (this.fault[i] == -1) {
for (int j = i; j < this.id - 1; j++) {
this.fault[j] = this.fault[j + 1];
}
this.id--;
}
}
System.out.println("错题展示完毕");
}
}