#include <iostream>
#include <sstream>
#include <stack>
#include <limits>
#include <string>
using namespace std;

int main()
{
    string input;
    cout << "Enter a postfix expression: " << endl;
    getline(cin, input);

    int operand1, operand2, result,number;
    stack<char>operation;

    stringstream temp;

    int i=0;
    while (i < input.length())
    {
        if (isdigit(input[i]))
        {
            operation.push(input[i]);
        }
        else
        {
            operand2 = operation.top();
            temp << operation.top();
            operation.pop();

            operand1 = operation.top();
            temp << operation.top();
            operation.pop();

            switch(operand1,operand2)
            {
                case '+': result=operand1 + operand2;
                break;

                case '-': result=operand1 - operand2;
                break;

                case '*': result=operand1 * operand2;
                break;

                case '/': result=operand1 / operand2;
                break;
            }
            operation.push(result);
        }
        i++;
    }
    cout << "The result is: "<<temp.str()<<endl;
    cin.ignore(numeric_limits<streamsize>::max(), '\n');

    return 0;
}


我已经更改了代码并设法获得了“ pop”值,但是该操作无效。

最佳答案

你可能是说

switch(input[i])


代替

switch(operation.top())

关于c++ - 使用C++中的堆栈评估postfix,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/5631345/

10-11 19:13