// 进行运算
private double Calculate(string operators, string numbers) {
// 将数字和操作符字符串存到数组当中
string[] numberarray = Regex.Split(numbers, " ");
string[] operatorarray = Regex.Split(operators, " ");
Stack numberStack = new Stack();// 数字栈
Stack operatorStack = new Stack();// 操作符栈
// 先将前两个数字和一个操作符push到栈中
numberStack.Push(Convert.ToDouble(numberarray[0]));
numberStack.Push(Convert.ToDouble(numberarray[1]));
operatorStack.Push(operatorarray[0]);
// 当遍历完操作符数组且栈中操作符为空时跳出循环
for (int i = 1; i < operatorarray.Length || !operatorStack.IsEmpty();) {
// 当操作符栈为空时，push一个数字和一个操作符
if (operatorStack.IsEmpty()) {
numberStack.Push(Convert.ToDouble(numberarray[i + 1]));
operatorStack.Push(operatorarray[i]);
i++;continue;
}
// 当栈顶操作符为+或者-时
if (operatorStack.getTop().Equals("+") || operatorStack.getTop().Equals("-")) {
if (i < operatorarray.Length) { // 当下一个操作符不是最后一个操作符时
// 如果下一个操作符为*或者/，则push一个数字和操作符
if (operatorarray[i].Equals("*") || operatorarray[i].Equals("/")) {
numberStack.Push(Convert.ToDouble(numberarray[i + 1]));
operatorStack.Push(operatorarray[i]);
i++;
} else {// 否则，栈内进行加减运算，将结果push到栈顶，下同
double after = Convert.ToDouble(numberStack.Pop());
double pre = Convert.ToDouble(numberStack.Pop());
string op = operatorStack.Pop().ToString();
switch (op) {
case "+": { numberStack.Push(pre + after); continue; }
case "-": { numberStack.Push(pre - after); continue; }
default: continue;
}
}
} else {// 如果没有下一个操作符，则栈内进行加减运算
double after = Convert.ToDouble(numberStack.Pop());
double pre = Convert.ToDouble(numberStack.Pop());
string op = operatorStack.Pop().ToString();
switch (op) {
case "+": { numberStack.Push(pre + after); continue; }
case "-": { numberStack.Push(pre - after); continue; }
default: continue;
}
}
} else {// 如果栈顶操作符为*或者/，则栈内直接进行乘除运算
double after = Convert.ToDouble(numberStack.Pop());
double pre = Convert.ToDouble(numberStack.Pop());
string op = operatorStack.Pop().ToString();
switch (op) {
case "*": { numberStack.Push(pre * after); continue; }
case "/": { numberStack.Push(pre / after); continue; }
default: continue;
}
}
}
// 取出栈顶元素作为结果返回
object result = numberStack.Pop();
return Convert.ToDouble(result);
}