# V3025\. 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, Console\.WriteLine, Console\.Write, etc\. The format string does not correspond with actual arguments passed to the method\.

Here are some simple examples:

**Unused arguments\.**

```cpp
int A = 10, B = 20;
double C = 30.0;
Console.WriteLine("{0} < {1}", A, B, C);
```

Format item \{2\} is not specified, so variable 'C' won't be used\.

Possible correct versions of the code:

```cpp
//Remove extra argument
Console.WriteLine("{0} < {1}", A, B);

//Fix format string
Console.WriteLine("{0} < {1} < {2}", A, B, C);
```

**Number of arguments passed is less than expected\.**

```cpp
int A = 10, B = 20;
double C = 30.0;
Console.WriteLine("{0} < {1} < {2}", A, B);
Console.WriteLine("{1} < {2}", A, B);
```

A much more dangerous situation occurs when a function receives fewer arguments than expected\. This will raise a FormatException exception\.

Possible correct versions of the code:

```cpp
//Add missing argument
Console.WriteLine("{0} < {1} < {2}", A, B, C);

//Fix indices in format string
Console.WriteLine("{0} < {1}", A, B);
```

**The analyzer doesn't output the warning given that:**

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

```cpp
int row = 10;
Console.WriteLine("Line: {0}; Index: {0}", row);
```

Here is an example of this bug in a real\-life application:

```cpp
var sql = string.Format(
  "SELECT {0} FROM (SELECT ROW_NUMBER() " +
  " OVER (ORDER BY {2}) AS Row, {0} FROM {3} {4}) AS Paged ",
  columns, pageSize, orderBy, TableName, where);
```

The function receives 5 formatting objects, but the 'pageSize' variable is not used as format item \{1\} is missing\.