Go vs. C: How Do Floating-Point Precision Differences (Float32 vs. Float64) Affect Program Behavior?

Float Point Precision: Float32 vs Float64 in Go

To investigate the disparity in behavior between Go and C programs utilizing floating-point values, let's delve into the fascinating world of IEEE 754 binary representation.

Representing Float Values in Go and C

Using the math.Float32bits and math.Float64bits functions, we can unveil the binary representations of different decimal values in Go:

import "math"

func main() {
    fmt.Println(math.Float32bits(0.1))
    fmt.Println(math.Float32bits(0.2))
    fmt.Println(math.Float32bits(0.3))
    fmt.Println(math.Float64bits(0.1))
    fmt.Println(math.Float64bits(0.2))
    fmt.Println(math.Float64bits(0.3))
}

Deviations in Binary Representations

Upon converting these binary representations to decimal, we uncover a discrepancy between float32 and float64 values:

• float32(0.1): 0.10000000149011612
• float64(0.1): 0.10000000000000001

This indicates that Go rounds the last bit of float32 values, while C behaves differently.

C's Interpretation of Floats

The C standard permits implementations to handle float constants in varying ways. In the specific implementation tested, the value of 0.1 was rounded differently than in Go, leading to the discrepancy in loop iterations.

Conclusion

The nuanced treatment of floating-point values in Go and C underscores the importance of understanding data representation for accurate and predictable code behavior.

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