// -----------------------------------------------------------------------------
// Demonstrates how to check whether a floating‑point value (f64) is an integer.
// Uses a small tolerance to safely handle floating‑point precision issues.
// Rust's f64 behaves like a double in many languages.
// -----------------------------------------------------------------------------
fn is_integer(value: f64) -> bool {
// A tiny tolerance helps avoid floating‑point precision errors.
const EPSILON: f64 = 1e-12;
// floor() returns the largest integer <= value.
let floored = value.floor();
// If the absolute difference is extremely small, treat the number as integer.
(value - floored).abs() < EPSILON
}
// -----------------------------------------------------------------------------
// Prints a descriptive message for the given floating‑point value.
// -----------------------------------------------------------------------------
fn print_check(value: f64) {
println!("Checking value: {:.15}", value);
if is_integer(value) {
println!("Result: The value contains an integer.\n");
} else {
println!("Result: The value contains a floating‑point number.\n");
}
}
// -----------------------------------------------------------------------------
// Entry point demonstrating several example values.
// -----------------------------------------------------------------------------
fn main() {
// Example input values (Rust f64 behaves like a double)
let a: f64 = 42.0; // integer-like
let b: f64 = 42.00000000001; // floating-point due to tiny fraction
let c: f64 = 89.0000000000001; // integer-like
let d: f64 = -7.0; // negative integer-like
let e: f64 = 3.14; // floating-point
// Run checks
print_check(a);
print_check(b);
print_check(c);
print_check(d);
print_check(e);
}
/*
run:
Checking value: 42.000000000000000
Result: The value contains an integer.
Checking value: 42.000000000009997
Result: The value contains a floating‑point number.
Checking value: 89.000000000000099
Result: The value contains an integer.
Checking value: -7.000000000000000
Result: The value contains an integer.
Checking value: 3.140000000000000
Result: The value contains a floating‑point number.
*/
