Question

我正在尝试将其从java转换为C＃并且除了tokenizer之外几乎完成了所有这些操作。我知道你在C＃中使用split，但我似乎无法弄明白。程序需要拆分用户输入的等式（4/5 + 3/4）是没有括号的格式。任何帮助都会很棒。

// read in values for object 3
Console.Write("Enter the expression (like 2/3 + 3/4 or 3 - 1/2): ");
string line = Console.ReadLine();

// Works with positives and neagative values!
// Split equation into first number/fraction, operator, second number/fraction
StringTokenizer st = new StringTokenizer(line, " ");
string first = st.nextToken();
char op = (st.nextToken()).charAt(0);
string second = st.nextToken();

我稍后需要symobol（+， - ，*或/），并且需要检查它是否是我在我的代码中执行的整数。下面是我尝试的一种，但我坚持使用char。

char delimeters = ' ';
string[] tokens = line.Split(delimeters);
string first = tokens[0];
char c = tokens[1]

Answer 1

tokens是一个字符串数组，因此token [1]是一个字符串，您不能将字符串赋给char。这就是javacode编写charAt(0)的原因。将其转换为C＃给出

char delimeters = ' ';
string[] tokens = line.Split(delimeters);
string first = tokens[0];
char c = tokens[1][0];

Answer 2

相当于Java的

String first = st.nextToken();
char op = (st.nextToken()).charAt(0);
String second = st.nextToken();

将是

string first = tokens[0];
char c = tokens[1][0];
string second = tokens[2];

最有可能的是，您需要在循环中执行此操作。 first将被阅读一次，然后您会在有更多数据的情况下阅读operator和operand，如下所示：

List<string> operands = new List<string> {tokens[0]};
List<char> operators = new List<char>();
for (int i = 1 ; i+1 < tokens.Length ; i += 2) {
    operators.Add(tokens[i][0]);
    operands.Add(tokens[i+1]);
}

在此循环之后，operators将包含代表运算符的N个字符，operands将包含代表操作数的N+1个字符串。

Answer 3

我刚刚对此进行了编码（即我没有尝试过）......但是现在你去了。

//you should end up with the following
// tokens[0] is the first value, 2/3 or 3 in your example
// tokens[1] is the operation, + or - in your example
// tokens[2] is the second value, 3/4 or 1/2 in your example

char delimeters = ' ';
string[] tokens = line.Split(delimeters);


char fractionDelimiter = '/';
// get the first operand
string first = tokens[0];
bool result = int.TryParse(first, out whole);
double operand1 = 0;

//if this is a fraction we have more work...
// we need to split again on the '/'
if (result) {
   operand1 = (double)whole;
} else {
   //make an assumption that this is a fraction

   string fractionParts = first.Split(fractionDelimiter);
   string numerator = fractionParts[0];
   string denominator = fractionParts[1];
   operand1 = int.Parse(numerator) / int.Parse(denominator);
}

// get the second operand
string second = tokens[2];
bool secondResult = int.TryParse(second, out secondWhole);
double operand2 = 0;

if (secondResult) {
   operand2 = (double)secondWhole;
} else {
   //make an assumption that this is a fraction

   string secondFractionParts = second.Split(fractionDelimiter);
   string secondNumerator= secondFractionParts[0];
   string secondDenominator = secondFractionParts[1];
   operand2 = int.Parse(secondNumerator) / int.Parse(secondDenominator);
}

其余的应该像找出操作是什么一样简单，并使用operand1和operand2进行操作

Tokenizer /拆分c＃？

3 个答案: