Convert Double Type Variables to Int in Haskell

In Haskell, we will convert double type variables into int by using user-defined function, doubleToInt along with floor, round and ceiling functions. In the first example, we are going to use (doubleToInt d = floor d) function and in the second example, we are going to use (doubleToInt d = round d). And in the third example, we are going to use (doubleToInt d = ceiling d).

Algorithm

• Step 1 ? The doubleToInt function is defined using floor function as, doubleToInt d = floor d.

• Step 2 ? The program execution will be started from main function. The main() function has whole control of the program. It is written as main = do.

• Step 3 ? The variable named, "d" is being initialized. It will hold the double value that is to be converted to respective integer value.

• Step 4 ? The function, doubleToInt is being called and d is passed to it.

• Step 5 ? The resultant integer value is printed to the console using ?putStrLn' statement after the function is called.

Example 1

In this example, a function doubleToInt is defined that takes a Double value d and returns an Int value by using the floor function to round down to the nearest integer. It then defines a main function that calls doubleToInt with a Double value and prints out both the original Double value and the resulting Int value.

doubleToInt :: Double -> Int
doubleToInt d = floor d

main :: IO ()
main = do
   let d = 3.14159
       i = doubleToInt d
   putStrLn $ "The value of d is " ++ show d
   putStrLn $ "The value of i is " ++ show i

Output

The value of d is 3.14159
The value of i is 3

Example 2

In this example, the round function rounds the Double value to the nearest integer, and returns it as an Integral type, which can be directly converted to an Int.

doubleToInt :: Double -> Int
doubleToInt d = round d

main :: IO ()
main = do
   let d = 3.14159
       i = doubleToInt d
   putStrLn $ "The value of d is " ++ show d
   putStrLn $ "The value of i is " ++ show i

Output

The value of d is 3.14159
The value of i is 3

Example 3

In this example, the ceiling function rounds the Double value up to the nearest integer, and returns it as an Integral type, which can be directly converted to an Int.

doubleToInt :: Double -> Int
doubleToInt d = ceiling d

main :: IO ()
main = do
   let d = 3.14159
       i = doubleToInt d
   putStrLn $ "The value of d is " ++ show d
   putStrLn $ "The value of i is " ++ show i

Output

The value of d is 3.14159
The value of i is 4

Conclusion

Double to int conversion is the process of converting a Double data type to an Int data type. Double is a floating-point data type that can hold decimal values with high precision, while Int is an integer data type that can hold whole numbers only. In Haskell, an Int variable is converted to double using user-defined doubleToInt function along with floor, round and ceiling functions.