我需要編寫一個 Java 程序，從標準輸入中獲取有效的右括號中綴表達式 (RPIE) 并輸出等效的全括號中綴表達式 (FPIE)。例如，如果輸入是：a+20)/bc) 53.4-d)))，則輸出應該是 ((a+20)/((bc) (53.4-d)))。我嘗試如下實施，但沒有達到解決方案。有人可以幫我嗎？import java.util.Scanner;import java.util.Stack;public class ParenthesisCreator { static private String expression; private Stack<Character> stack = new Stack<Character>(); public ParenthesisCreator(String input) { expression = input; } public String rtParenthesisInfixToFullParenthesis() { String postfixString = ""; for (int index = 0; index < expression.length(); ++index) { char value = expression.charAt(index); if (value == ')') { stack.push(')'); stack.push('('); Character oper = stack.peek(); while (!stack.isEmpty()) { stack.pop(); postfixString += oper.charValue(); if (!stack.isEmpty()) oper = stack.peek(); } } else { postfixString += value; } } return postfixString; } public static void main(String[] args) { System.out.println("Type an expression written in right parenthesized infix: "); Scanner input = new Scanner(System.in); String expression = input.next(); // Input: a+20)/b-c)*53.4-d))) // Desired output is: ((a+20)/((b-c)*(53.4-d))) ParenthesisCreator convert = new ParenthesisCreator(expression); System.out.println("This expression writtien in full parenthesized is: \n" + convert.rtParenthesisInfixToFullParenthesis()); }}
2 回答
慕桂英546537
TA貢獻1848條經驗 獲得超10個贊
public final class ParenthesisCreator implements Function<String, String> {
private final IntPredicate isOperator;
public ParenthesisCreator() {
this(ch -> ch == '/' || ch == '*' || ch == '+' || ch == '-');
}
public ParenthesisCreator(IntPredicate isOperator) {
this.isOperator = isOperator;
}
@Override
public String apply(String expr) {
Deque<String> stack = new LinkedList<>();
StringBuilder buf = null;
for (int i = 0; i < expr.length(); i++) {
char ch = expr.charAt(i);
if (ch == ')') {
if (buf != null) {
stack.push(buf.insert(0, '(').append(')').toString());
buf = null;
} else if (stack.size() >= 2) {
String two = stack.pop();
String one = stack.pop();
stack.push('(' + one + two + ')');
} else
throw new IllegalArgumentException();
} else if (isOperator.test(ch) && buf == null && !stack.isEmpty())
stack.push(stack.pop() + ch);
else
(buf = buf == null ? new StringBuilder() : buf).append(ch);
}
return String.join("", stack);
}
}
System.out.println(new ParenthesisCreator().apply("a+20)/b-c)53.4-d)))")); // ((a+20)/((b-c)(53.4-d)))
撒科打諢
TA貢獻1934條經驗 獲得超2個贊
public class FixExpressionParentheses {
public String fixExpression(String expression) {
String[] tokenArray = expression.split(" ");
Stack<String> operators = new Stack<>();
Stack<String> operands = new Stack<>();
for (String token: tokenArray) {
switch (token) {
case "+", "-", "*", "/", "sqrt" -> operators.push(token);
case ")" -> {
String operator = operators.pop();
String operandTwo = operands.pop();
String operandOne = operands.pop();
String newToken = "( " + operandOne + " " + operator + " "
+ operandTwo + " )";
operands.push(newToken);
}
default -> operands.push(token);
}
}
return operands.pop();
}
}
添加回答
舉報
0/150
提交
取消