返回的字符与存储的字符不同。

Question

当我使用中缀为73 + 2 *时，字符不会以当前形式存储。它打印其他值。它应该将第一个操作数打印为7，但打印其他内容。

public char postfixOperation(String infix) {
    operatorStack.reset();
    int firstOperand=0;
    int secondOperand=0;
    for(int j=0;j<infix.length();j++){    // loop until the end of the line for a string (expression)
        // Check for numbers 
        if( infix.charAt(j) =='0' || infix.charAt(j) =='1' || infix.charAt(j) =='2'|| infix.charAt(j) 
        =='3'|| infix.charAt(j) =='4'|| infix.charAt(j) =='5'|| infix.charAt(j) =='6'|| infix.charAt(j) 
        =='7'|| infix.charAt(j) =='8'|| infix.charAt(j) =='9' ){
            operatorStack.push(infix.charAt(j));
                        }
        //check for '+'
        else if( infix.charAt(j)=='+'){
            firstOperand = operatorStack.pop(); // pop first operand
            System.out.println(firstOperand);
            secondOperand = (int) operatorStack.pop(); // pop second operand
            operatorStack.push((char) (firstOperand + secondOperand));
        }
        //check for '-'


       else if( infix.charAt(j)=='-'){
            firstOperand = (int) operatorStack.pop();   // pop first operand
            secondOperand = (int) operatorStack.pop(); // pop second operand
            operatorStack.push((char) (firstOperand - secondOperand));
        }
        //check for '*'
        else if( infix.charAt(j)=='*'){
            firstOperand = (int) operatorStack.pop();   // pop first operand
            secondOperand = (int) operatorStack.pop(); // pop second operand
            operatorStack.push((char) (firstOperand * secondOperand));
        }
        //check for '/'
        else if( infix.charAt(j)=='/'){
            firstOperand = (int) operatorStack.pop();   // pop first operand
            secondOperand = (int) operatorStack.pop(); // pop second operand
            operatorStack.push((char) (firstOperand / secondOperand));
        }

    }        
    return operatorStack.pop();
}

Answer 1

您继续使用char变量并对其数值执行操作。这意味着，例如，'9' - '7' == 2，而不是'2'。而是从输入字符中减去'0'并改为使用数值。