解析 java 中的数据

Question

I am using

i=sscanf(input,"%f %c %f",&operand1,operator,&operand2);

in C for parsing the input which is of the format

operand1   operator  operand2

operator can be + - * / ^
operand + or - any double

is there any method similar in JAVA

Answer 1

a convenient option is to use the java.util.Scanner -class. The following code snippet should get you going to parse inputs:

import java.util.Scanner; 

public class ScannerExample {
    public static void main(String args[]) {
      // Declare variables
      Scanner s;
      float f1;
      float f2;
      char op;
      
      // Ask for input data
      System.out.println("Enter Data: ");

      // Initialize a Scanner-object using stdin
      s = new Scanner(System.in);
      
      // Read and parse the data
      f1 = s.nextFloat();
      op = s.next().charAt(0);
      f2 = s.nextFloat();
      
      System.out.println(f1 + " " + op + " " + f1);

      // Closes the scanner
      s.close();
    }
}

Error checking was omitted for the sake of brevity.

Edit: As @electricchef pointed out, one could also use the useDelimiter(Pattern pattern) -function of Scanner as an alternative approach, like so:

s = new Scanner(System.in);
s.useDelimiter("\\s+");
f1 = s.nextFloat();
op = s.next().charAt(0);
f2 = s.nextFloat();

Here, the input is splitted at one or more whitespace-characters as it is denoted by the regex-pattern "\\s+" .