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Java Java Basics Getting Started with Java Strings and Variables

Adam Sawicki
Adam Sawicki
15,967 Points
Posted by Adam Sawicki
Adam Sawicki
15,967 Points

System.out println

Hey, I wonder what is the difference between using console class (method printf) and using System.out.println. In second case you don't have to import extra library.

3 Answers

Evan Demaris
Evan Demaris
64,262 Points
Evan Demaris
Evan Demaris
64,262 Points

I think some more complicated examples from the Java Documentation would be helpful to illustrate how printf is best used; it's not just a replacement for concatenating variables, as it will format the variable as defined by the converter/flag included.

      long n = 461012;
      System.out.format("%d%n", n);      //  -->  "461012"
      System.out.format("%08d%n", n);    //  -->  "00461012"
      System.out.format("%+8d%n", n);    //  -->  " +461012"
      System.out.format("%,8d%n", n);    // -->  " 461,012"
      System.out.format("%+,8d%n%n", n); //  -->  "+461,012"

      double pi = Math.PI;
      System.out.format("%f%n", pi);       // -->  "3.141593"
      System.out.format("%.3f%n", pi);     // -->  "3.142"
      System.out.format("%10.3f%n", pi);   // -->  "     3.142"
      System.out.format("%-10.3f%n", pi);  // -->  "3.142"
      System.out.format(Locale.FRANCE, "%-10.4f%n%n", pi); // -->  "3,1416"

      Calendar c = Calendar.getInstance();
      System.out.format("%tB %te, %tY%n", c, c, c); // -->  "May 29, 2006"
      System.out.format("%tl:%tM %tp%n", c, c, c);  // -->  "2:34 am"
      System.out.format("%tD%n", c);    // -->  "05/29/06"

The link to the Java docs above includes a full list of the converters and flags used in these examples, if you're interested.

Evan Demaris
Evan Demaris
64,262 Points
Evan Demaris
Evan Demaris
64,262 Points

Hi Adam,

The biggest difference upfront is that you can use printf to format a string with variables.

System.out.printf("The value of the float variable is %f," +
"while the value of the integer variable is %d, " +
"and the string is %s", floatVar, intVar, stringVar);

Hope that helps!

Adam Sawicki
Adam Sawicki
15,967 Points
Adam Sawicki
Adam Sawicki
15,967 Points

That's right but why this is better than System.out.println("blablabla" + var1 + "blablabla" + var2 )? I can see the advantage that you can all variables in one place but there is more?