# V8013\. Incorrect format\. A different number of format items is expected\.

The analyzer has detected an error when the format I/O function was used\. The number of passed arguments does not match what is expected according to the format string\.

Here are some examples where the analyzer issues warnings\.

Example N1:

```cpp
fmt.Printf("Name: %s; Age: %d", "Donald")
```

The format string expects a name \(`%s`\) and an age \(`%d`\), but the argument for the age is missing\. As a result, `stdout` outputs a malformed string\.

To fix this, pass the age as the next argument:

```cpp
fmt.Printf("Name: %s; Age: %d", "Donald", 13)
```

Example N2:

```cpp
fmt.Printf("Name: %s", "Donald", 13)
```

The function here receives more arguments than intended\. The `13` argument has no placeholder in the format string\. In this case, `stdout` also prints a malformed string\.

To fix this, remove the redundant argument: 

```cpp
fmt.Printf("Name: %s", "Donald")
```

You can use the passed arguments to set the width and precision of the format item\.

Take a look at a width example:

```cpp
fmt.Printf("Name: %*s", "Donald")
```

The format string defines the width using the `*` symbol, but the corresponding argument is missing\.

To fix this, add the missing argument that specifies the width:

```cpp
fmt.Printf("Name: %*s", 10, "Donald")
```

The analyzer also issues warnings about precision\-related issues that can be specified using the `.*` sequence\.

You can explicitly specify the argument index to be substituted into a given format element \(similar to width and precision\)\. Note that the next argument index comes from the index of the previous substitution argument, except for the first one\. As a result, if you explicitly specify that the `n` argument should be substituted, the `n + 1` argument will follow it\. 

Look at the example: 

```cpp
fmt.Printf("2: %[2]s, 1: %[1]s, 3: %s", "Donald", "James", "Michael")
```



In this case, the following will appear in the `stdout`:

```cpp
2: James, 1: Donald, 3: James
```

The `"Michael"` argument is ignored\. This happens because the first argument `%[1]s` is substituted before it\. So, next argument used for substitution will be the second one, corresponding to `James`\. 

To fix this, explicitly specify the index of the argument that should match the last format item: 

```cpp
fmt.Printf("2: %[2]s, 1: %[1]s, 3: %[3]s",
           "Donald", "James", "Michael")
```

Now, `stdout` will output the correct string: 

```cpp
2: James, 1: Donald, 3: Michael
```