[英]Create an equation using Random and operators in Java
我正在嘗試創建一種方法,該方法可以為我創建一個字符串形式的方程式。
例如,此方法將創建:
字符串公式=“ 5 + 3”;
那么另一種方法將解決它。
我真的不知道如何創建字符串。 我應該使用concat嗎?
感謝您的所有幫助。
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;
}
很快就寫了一些東西,我認為這應該可以幫助您。 不過,您必須處理括號。 我沒有說明。
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);
}
}
我可能會稍后再回來解決括號問題。 現在,我只打印應該處理括號的“ P”。
編輯更新它來處理括號。 我將其粘貼在這里,以防您想保留它的舊方法。 還做了一些在這里和那里的調整。 請注意,在括號中,我沒有匹配確切數量的運算符。 這意味着,如果在循環抓取運算符之前尚未關閉所有打開的括號,那么我將在結尾處附加額外的括號。 這可能導致7個以上的運算符。 您可能應該添加邏輯以將一對括號視為1個運算符或將1個括號視為單個運算符。 請享用。
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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