# V6046. Incorrect format. Consider checking the N format items of the 'Foo' function.

The analyzer has detected a possible error related to use of formatting methods: String.format, System.out.format, System.err.format, etc. The format string does not correspond with actual arguments passed to the method.

Here are some simple examples:

Unused arguments.

    int A = 10, B = 20;
    double C = 30.0;
    System.out.format("%1$s < %2$s", A, B, C);

Format item '%3$s' is not specified, so variable 'C' won't be used.

Possible correct versions of the code:

    //Remove extra argument
    System.out.format("%1$s < %2$s", A, B);

    //Fix format string
    System.out.format("%1$s < %2$s < %3$s", A, B, C);

Number of arguments passed is less than expected.

    int A = 10, B = 20;
    double C = 30.0;
    System.out.format("%1$s < %2$s < %3$s", A, B);

A much more dangerous situation occurs when a function receives fewer arguments than expected. This leads to an exception.

Possible correct versions of the code:

    //Add missing argument
    System.out.format("%1$s < %2$s < %3$s", A, B, C);

    //Fix indices in format string
    System.out.format("%1$s < %2$s", A, B);

The analyzer doesn't output the warning given that:

- The number of format items specified matches the number of arguments.
- The format object is used a number of times:

    int row = 10;
    System.out.format("Line: %1$s; Index: %1$s", row);

This diagnostic is classified as:

CWE-628 CWE-685 CWE-686

You can look at examples of errors detected by the V6046 diagnostic.