processExpression - this method should take a String in the format: "integer [[+-*/] integer]*]" Your method should then process this expression and return the result as an integer
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To implement the processExpression method, you will need to perform the following steps:
1. Split the input string into individual tokens. In this case, the tokens are integers and the arithmetic operators (+, -, *, /). You can use the String class's split() method to split the string using a regular expression:
```java
String[] tokens = expression.split("\\s");
```
Here, "\\s" is a regular expression pattern that matches any whitespace character, which effectively splits the expression into tokens separated by spaces.
2. Initialize the result variable to the first integer in the expression. Parse the first token as an integer and set the result to its value:
```java
int result = Integer.parseInt(tokens[0]);
```
3. Iterate over the remaining tokens in the expression. Start the loop from index 1, as the first token has already been processed:
```java
for (int i = 1; i < tokens.length; i += 2) {
// Process each operator and its corresponding operand
}
```
Here, we increment the index by 2 to ensure we only process the operators and operands.
4. Inside the loop, determine the operator and the operand for the current iteration. Retrieve the operator as a character and parse the operand as an integer:
```java
char operator = tokens[i].charAt(0);
int operand = Integer.parseInt(tokens[i + 1]);
```
5. Perform the arithmetic operation based on the operator and the operand, updating the result accordingly:
```java
switch (operator) {
case '+':
result += operand;
break;
case '-':
result -= operand;
break;
case '*':
result *= operand;
break;
case '/':
result /= operand;
break;
}
```
6. After the loop, the result variable will contain the final value of the expression. Return it as an integer:
```java
return result;
```
By following these steps, you can implement the processExpression method to process the given expression string and return the result as an integer.