Floating-Point Numbers

If we try to store a decimal number in an integer variable, it will give us an error:

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              12
            
var myVariable int
myVariable = 7.9 // Error in this line

To store decimal values, a different data type is needed. In programming languages, including Go, we use floating-point numbers, often referred to as floats, to represent decimal numbers.

In Go, floating-point numbers come in two types: float32 and float64. float32 is a 32-bit type with limited precision, suitable for a broad range of decimal values when memory efficiency is crucial. Conversely, float64 is a 64-bit type referred to as "double precision" and provides greater accuracy, making it the default choice for most calculations requiring precision.

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              12345678910
            
package main
import "fmt"

func main() {
    var myFloatValue1 float32 = 3.1415926535
    var myFloatValue2 float64 = 3.1415926535
   
    fmt.Println("float32:", myFloatValue1)
    fmt.Println("float64:", myFloatValue2)
}

In the output of the program above, you can observe that the myFloatValue1 variable, which is of type float32, retains up to 7 decimal points. It's worth noting that the last digit is rounded to 7, resulting in an output of 3.1415927 instead of the original 3.1415926535.

Conversely, myFloatValue2 outputs the complete high-precision value 3.1415926535.

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Seção 2. Capítulo 2