[英]Create an equation using Random and operators in Java
我正在尝试创建一种方法,该方法可以为我创建一个字符串形式的方程式。
例如,此方法将创建:
字符串公式=“ 5 + 3”;
那么另一种方法将解决它。
我真的不知道如何创建字符串。 我应该使用concat吗?
感谢您的所有帮助。
public static String getEquation() {
for(int i=0;i<7;i++){
int rand = rng.nextInt(5);
switch (rand) {
case 0:
operator = "+";
break;
case 1:
operator = "-";
break;
case 2:
operator = "*";
break;
case 3:
operator = "/";
break;
case 4:
operator = "(";
break;
case 5:
operator = ")";
}
}
return formula;
}
很快就写了一些东西,我认为这应该可以帮助您。 不过,您必须处理括号。 我没有说明。
import java.util.Random;
public class Test {
static Random randomGenerator = new Random();
static String operators = "+-*/P"; //p = parentheses pair
public static char getRandomOperator() {
return operators.charAt(randomGenerator.nextInt(operators.length()));
}
public static int getRandomNumber() {
return randomGenerator.nextInt(100);
}
public static String createEquation() {
//Just for proof of concept, let's do 3 operators
String equation = "";
int numOfOperators = 3;
char operator = ' ';
for (int i = 0; i < numOfOperators; i++) {
equation += getRandomNumber();
equation += getRandomOperator();
}
equation += getRandomNumber();
return equation;
}
public static void main(String[] args) {
String equation = createEquation();
System.out.println(equation);
}
}
我可能会稍后再回来解决括号问题。 现在,我只打印应该处理括号的“ P”。
编辑更新它来处理括号。 我将其粘贴在这里,以防您想保留它的旧方法。 还做了一些在这里和那里的调整。 请注意,在括号中,我没有匹配确切数量的运算符。 这意味着,如果在循环抓取运算符之前尚未关闭所有打开的括号,那么我将在结尾处附加额外的括号。 这可能导致7个以上的运算符。 您可能应该添加逻辑以将一对括号视为1个运算符或将1个括号视为单个运算符。 请享用。
import java.util.Random;
public class Test {
static Random randomGenerator = new Random();
static String operators = "+-*/()";
static int opeatorStringLength = operators.length();
public static char getRandomOperator() {
return operators.charAt(randomGenerator.nextInt(opeatorStringLength));
}
public static int getRandomNumber() {
return randomGenerator.nextInt(100);
}
public static String appendToEquation(String equation, String value1, String value2) {
String temp = equation;
temp += value1;
temp += value2;
return temp;
}
public static String createEquation(int numOfOperators) {
String equation = "";
char operator;
int operand;
int openParenCounter = 0;
for (int i = 0; i < numOfOperators; i++) {
operator = getRandomOperator();
operand = getRandomNumber();
if (operator == '(') {
openParenCounter++;
equation = appendToEquation(equation, Character.toString(operator), Integer.toString(operand));
} else if (operator == ')') {
if (openParenCounter == 0) { //Can't start off with a close parenthesis
openParenCounter++;
equation = appendToEquation(equation, "(", Integer.toString(operand));
} else {
openParenCounter--;
equation = appendToEquation(equation, Integer.toString(operand), Character.toString(operator));
}
} else {
equation = appendToEquation(equation, Integer.toString(operand), Character.toString(operator));
}
}
equation += getRandomNumber();
while (openParenCounter > 0) {
equation += ")";
openParenCounter--;
}
return equation;
}
public static void main(String[] args) {
String equation;
equation = createEquation(7); //The argument passed is the number of operators to use
System.out.println(equation);
}
}
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