The **`compareTo` function** in Scala checks whether two strings are the same or not. It is applied on a `string`. 

It takes in a single parameter: the `string` to compare with. It returns *zero* if both strings are the same, a *negative number* if the first string is less than the second, and a *positive number* if the first string is greater than the second.

The illustration below shows how  `compareTo` works in Scala:

# Definition

The `compareTo` function is defined as follows:

``` Scala
int compareTo(String second)
```

# Return value

The `compareTo` function returns *zero* if both strings are the same, a *negative number* if the first string is less than the second, and a *positive number* if the first string is greater than the second.

> Negative and positive numbers are based on the difference in character values between the first and second strings.

# Examples
 
The following example shows the `compareTo` function with the same strings:

> Zero is returned.

object Compare extends App {   
  
    val string1 = "Apple"
    val result = string1.compareTo("Apple")
    println(result)
  
} 


The following example shows the `compareTo` function with the first string less than the second:

> A negative number is returned.

object Compare extends App {   
  
    val string1 = "Ant"
    val result = string1.compareTo("Apple")
    println(result)
  
} 

The following example shows the `compareTo` function with the first string greater than the second:

> A positive number is returned.

object Compare extends App {   
   val string1 = "Apple"
    val result = string1.compareTo("Ant")
    println(result)
  
} 

What is compareTo in Scala?

compareTo in Scala checks if two strings are the same, returning zero, negative, or positive.