package formula;

import java.util.ArrayList;public class Formula {public static enum Operators {ADD, // 加SUB, // 减MUL, // 乘DIV  // 除
    }public Operators operator = Operators.ADD; // 实际运算符，用于运算。public int integer = 0; // 整数部分public int numerator = 0; // 分子public int denominator = 1; // 分母public int symbol = 1; // 代表正负public ArrayList<Formula> list; // 多项式/*** 初始化空单项式*/public Formula() {list = null;}/*** 初始化单项式*/public Formula(Operators operator) {this.operator = operator;list = null;}/*** 生成自然数单项式* @param operator 运算符* @param integer 整数部分*/public Formula(Operators operator, int integer){this.operator = operator;if(integer > 0){this.integer = integer;}else {this.integer = -1 * integer;this.symbol = -1;}list = null;}/*** 生成分数单项式* @param operator* @param numerator* @param denominator*/public Formula(Operators operator, int numerator, int denominator){this.operator = operator;this.integer = numerator / denominator;if(numerator * denominator < 0) { // 整数部分this.symbol =  -1; // 数值正负this.integer = -1 * this.integer; // 正化
        }numerator = numerator % denominator; // 求余numerator = numerator < 0 ? -1 * numerator: numerator; // 正化denominator = denominator < 0 ? -1 * denominator: denominator; // 正化if(numerator > 0){ // 约分int a, b, c;a = denominator;b = numerator;while ((c = a % b) != 0){a = b;b = c;}this.numerator = numerator / b;this.denominator = denominator / b;}list = null;}/*** 生成单项式* @param operator 运算符* @param integer 整数部分* @param numerator 分子* @param denominator 分母*/public Formula(Operators operator, int integer, int numerator, int denominator){this.operator = operator;if(denominator < 0){denominator = -1 * denominator;numerator = -1 * numerator;}numerator = integer * denominator + numerator;this.integer = numerator / denominator;if(numerator * denominator < 0) { // 整数部分this.symbol =  -1; // 数值正负this.integer = -1 * this.integer; // 正化
        }numerator = numerator % denominator; // 求余numerator = numerator < 0 ? -1 * numerator: numerator; // 正化denominator = denominator < 0 ? -1 * denominator: denominator; // 正化if(numerator > 0){ // 约分int a, b, c;a = denominator;b = numerator;while ((c = a % b) != 0){a = b;b = c;}this.numerator = numerator / b;this.denominator = denominator / b;}list = null;}/*** 生成多项式* @param operator* @param list*/public Formula(Operators operator, ArrayList<Formula> list){this.operator = operator;this.list = list;this.injectFormulaValue();}/*** 无打印* @return 返回式子字符串*/public String _print(){String str = "";if(list == null || list.size() == 0) { // 单项式if(numerator > 0 && denominator > 0) str = numerator + "/" + denominator;if(integer > 0) {if(str != "") str = integer + "'" + str;else str = integer + "";}if(str == "") str = "0";else if(symbol == -1) str += "( - "+ str +")";} else { // 多项式int length = list.size();for(int i = 0; i < length; i++){Formula item = list.get(i);if(i == 0) { // 首项if(item.operator == Operators.SUB) str += " - ";}else {switch (item.operator){case SUB: str += " - ";break;case ADD: str += " + ";break;case MUL: str += " * ";break;case DIV: str += " ÷ ";break;}}if(item.list != null && item.list.size() > 1) str += '('+ item._print() +')';else str += item._print();}}return str;}/*** 控制台输出式子* @return 式子字符串*/public String print(){String str = this._print() + " = ";System.out.println(str);return str;}/*** 记录式子数值* @param*/public void injectFormulaValue(){if(list == null) return;int length = list.size(),start = 0,end = 0;if(length < 1) return;// 计算式子值Formula a, b, c = null;a = new Formula();for(int i = 0; i < length; i++){b = list.get(i);if(b.operator == Operators.DIV || b.operator == Operators.MUL){a = this.mergeValue(a, b);}else {if(c == null) c = a;else c = mergeValue(c, a);a = b;}}c = mergeValue(c, a);// 记录值this.integer = c.integer;this.numerator = c.numerator;this.denominator = c.denominator;this.symbol = c.symbol;}/*** 合并数值* @param x* @param y* @return 返回最终数值*/public Formula mergeValue(Formula x, Formula y){switch (y.operator){case MUL: return this._mul(x, y);case DIV: return this._div(x, y);case SUB: return this._sub(x, y);default: return this._add(x, y);}}/*** 加法* @param x* @param y* @return*/public Formula _add(Formula x, Formula y){int numerator, denominator, numeratorX, numeratorY;denominator = x.denominator * y.denominator; // 分母numeratorX = (x.integer * denominator + x.numerator * y.denominator) * x.symbol; // x 分子numeratorY = (y.integer * denominator + y.numerator * x.denominator) * y.symbol; // y 分子numerator = numeratorX + numeratorY; // 分子和return new Formula(x.operator, numerator, denominator);}/*** 减法* @param x* @param y* @return*/public Formula _sub(Formula x, Formula y){int numerator, denominator, numeratorX, numeratorY;denominator = x.denominator * y.denominator; // 分母numeratorX = (x.integer * denominator + x.numerator * y.denominator) * x.symbol; // x 分子numeratorY = (y.integer * denominator + y.numerator * x.denominator) * y.symbol; // y 分子numerator = numeratorX - numeratorY; // 分子和return new Formula(x.operator, numerator, denominator);}/*** 除法* @param x* @param y* @return*/public Formula _div(Formula x, Formula y){int numerator, denominator, numeratorX, numeratorY;numeratorX = (x.integer * x.denominator + x.numerator) * x.symbol;numeratorY = (y.integer * y.denominator + y.numerator) * y.symbol;numerator = numeratorX * y.denominator;denominator = numeratorY * x.denominator;return new Formula(x.operator, numerator, denominator);}/*** 乘法* @param x* @param y* @return*/public Formula _mul(Formula x, Formula y){int numerator, denominator, numeratorX, numeratorY;Operators operator;numeratorX = (x.integer * x.denominator + x.numerator) * x.symbol;numeratorY = (y.integer * y.denominator + y.numerator) * y.symbol;numerator = numeratorX * numeratorY;denominator = x.denominator * y.denominator;return new Formula(x.operator, numerator, denominator);}/*** 判断正数* @return Boolean*/public Boolean isPositiveNumber(){return this.symbol == 1;}/*** 向多项式推入一项* @param x* @return*/public Boolean push(Formula x){if(this.list == null) this.list = new ArrayList<Formula>();int integer, denominator, numerator, symbol;integer = this.integer;denominator = this.denominator;numerator = this.numerator;symbol = this.symbol;this.list.add(x);this.injectFormulaValue();if(symbol != this.symbol){ // 结果为负数，失败this.list.remove(list.size() - 1);this.integer = integer;this.denominator = denominator;this.numerator = numerator;this.symbol = symbol;return false;}return true;} /*** 输出算式运算结果字符串* @return*/public String output(){String str = "";if(this.symbol == -1) str += "-";if(this.integer != 0) str += this.integer;if(this.denominator != 0 && this.numerator != 0) {if(this.integer != 0) str += "'" + this.numerator + "/" + this.denominator;else str += this.numerator + "/" + this.denominator;}if(this.integer == 0 && this.numerator == 0) str = "0";return str;}/*** 读取字符串* @param formula* @return*/public static Formula calculateFormulaString(String formula){if(formula == null) return new Formula();ArrayList<Formula> stack = new ArrayList<Formula>();stack.add(new Formula());Formula target = new Formula(), target2;int length = formula.length(), i = -1, position = 1;char c;Boolean isOk = true;Operators operator = Operators.ADD;while (++i < length){
//            System.out.println(i + " | " + length);c = formula.charAt(i);if(c == ' ') continue;else if(c == '('){stack.add(target);target = new Formula();} else if(c == ')'){int index = stack.size() - 1;target2 = stack.remove(index);target2.push(target);target = target2;position = 1;} else if(c == '+' || c == '-' || c == '*' || c == '÷') {stack.get(stack.size() - 1).push(target);switch (c){case '+': operator = Operators.ADD; break;case '-': operator = Operators.SUB; break;case '*': operator = Operators.MUL; break;case '÷': operator = Operators.DIV; break;}target = new Formula(operator);operator = Operators.ADD;position = 1;}else if(c == '\''){position = 2;}else if(c == '/'){if(position == 1){target.numerator = target.integer;target.integer = 0;}position = 3;target.denominator = 0;}else if(c <= '9' && c >= '0'){int value = Integer.parseInt(c + "");if(position == 1){target.integer = target.integer * 10 + value;}else if(position == 2) {target.numerator = target.numerator * 10 + value;}else if(position == 3) {target.denominator = target.denominator * 10 + value;}}else if(c == '=') break;else {System.out.println("- " + "未识别符号("+ (i+1) +")："+ c);isOk = false;break;}}
//        System.out.println("> "+formula);if(isOk){target2 = stack.get(0);target2.push(target);return stack.remove(0);}else {return new Formula();}}}

package formula;
import java.util.*;public class Create {Random r = new Random();ArrayList<Formula> list = new ArrayList<Formula>();Formula e;//生成式子中的第一个操作数（符号只能是+）public Formula CreateFirstOperand(int n){int a = r.nextInt(n) + 1; //随机产生1-n中的一个操作数int h = r.nextInt(n) + 1;int g = r.nextInt(h) + 1;int b = r.nextInt(2);if (b==0){e = new Formula(Formula.Operators.ADD, a);}else {e = new Formula(Formula.Operators.ADD, a, g, h);}return e;}//生成式子中其他的操作数，可以为+,-,*,/public Formula CreateOtherOperand(int n){int a = r.nextInt(n) + 1; //随机产生1-n中的一个操作数int h = r.nextInt(n) + 1;int g = r.nextInt(h) + 1;int b = r.nextInt(2);int c = r.nextInt(4);if(b==0){switch (c){case 0:e = new Formula(Formula.Operators.ADD, a);break;case 1:e = new Formula(Formula.Operators.SUB, a);break;case 2:e = new Formula(Formula.Operators.MUL, a);break;case 3:e = new Formula(Formula.Operators.DIV, a);break;}}else{switch (c){case 0:e = new Formula(Formula.Operators.ADD, a, g, h);break;case 1:e = new Formula(Formula.Operators.SUB, a, g, h);break;case 2:e = new Formula(Formula.Operators.MUL, a, g, h);break;case 3:e = new Formula(Formula.Operators.DIV, a, g, h);break;}}return e;}//随机生成多项式public  String CreateFormula(int p){String s = new String();Create n = new Create();Formula first,first2,second, third, fourth, i,j,k,l;i = new Formula();j = new Formula();l = new Formula();first = n.CreateFirstOperand(p);first2 = n.CreateFirstOperand(p);second = n.CreateOtherOperand(p);third = n.CreateOtherOperand(p);fourth = n.CreateOtherOperand(p);int OperandNumber = r.nextInt(3);switch (OperandNumber) {//两个操作数case 0:i.push(first);i.push(second);s = i._print();break;//三个操作数case 1:i.push(first);i.push(second);i.push(third);s = i._print();break;//四个操作数case 2:int a = r.nextInt(4);switch (a) {case 0:            //a+b+c+d
                                     i.push(first);i.push(second);i.push(third);i.push(fourth);s = i._print();break;case 1:int b = r.nextInt(2);switch (b) {case 0:              //(a+b+c)+d
                                             i.push(first);i.push(second);i.push(third);j.push(i);j.push(fourth);s = j._print();break;case 1:                //a+(b+c+d)int c = r.nextInt(3);switch (c) {case 0: k = new Formula(Formula.Operators.ADD);j = k;break;case 1: k = new Formula(Formula.Operators.SUB);j = k;break;case 2: k = new Formula(Formula.Operators.MUL);j = k;break;}i.push(first);j.push(first2);j.push(second);j.push(third);i.push(j);s = i._print();break;}break;case 2:int c = r.nextInt(3);int d = r.nextInt(3);switch (d) {case 0: k = new Formula(Formula.Operators.ADD);j = k;break;case 1: k = new Formula(Formula.Operators.SUB);j = k;break;case 2: k = new Formula(Formula.Operators.MUL);j = k;break;}switch (c) {case 0:              //(a+b)+c+d
                                              i.push(first);i.push(second);j.push(i);j.push(third);j.push(fourth);s = j._print();break;case 1:              //a+(b+c)+d
                                                  i.push(first);j.push(first2);j.push(second);i.push(j);i.push(third);s = i._print();break;case 2:               //a+b+(c+d)
                                                       i.push(first);i.push(second);j.push(first2);j.push(third);i.push(j);s = i._print();break;}break;case 3:       //(a+b)+(c+d)int e = r.nextInt(3);switch (e) {case 0: k = new Formula(Formula.Operators.ADD);j = k;break;case 1: k = new Formula(Formula.Operators.SUB);j = k;break;case 2: k = new Formula(Formula.Operators.MUL);j = k;break;}i.push(first);i.push(second);j.push(first2);j.push(third);l.push(i);l.push(j);s = l._print();break;}break;}return s;}
}

package formula;
import java.io.*;
import java.util.Scanner;public class Output {public static void main(String[] args)throws IOException{Create n = new Create();Formula b;int i, a, r,m;String[] t = new String[20000];Scanner sc = new Scanner(System.in);PrintStream questionout = new PrintStream("exercise.txt");PrintStream answerout = new PrintStream("answer.txt");System.out.println("请输入数值范围:");a = sc.nextInt();questionout.print("数字范围:" + a + "\t");System.out.println("请输入要生成的题目数量:");i = sc.nextInt();questionout.println("题目数量:" + i);for(m=1; m<=i; m++){t[m] = n.CreateFormula(a);questionout.println(m + "、" + t[m] + "=");b = Formula.calculateFormulaString(t[m]);answerout.println(m + "、" + b.output());}System.out.println("成功生成题目与答案");}
}