/*
format_decimal_with_zeros
-------------------------
Converts a floating‑point number into a fixed‑length string with
leading zeros on the integer part.
Parameters:
num - the decimal number to format
width - total width of the integer part (zero‑padded)
decimals - number of digits after the decimal point
Returns:
A formatted string such as "00003.14159"
Example:
num = 3.14159, width = 5, decimals = 5
Output → "00003.14159"
*/
fn format_decimal_with_zeros(num: f64, width: usize, decimals: usize) -> String {
// Split into integer and fractional parts
let integer_part = num.trunc() as i64;
let fractional_part = num - integer_part as f64;
// Format integer part with leading zeros
let int_str = format!("{:0width$}", integer_part, width = width);
// Format fractional part (starts with "0.xxx")
let frac_str = format!("{:.*}", decimals, fractional_part);
// Remove the leading "0" before the decimal point
format!("{}{}", int_str, &frac_str[1..])
}
fn main() {
let num = 3.14159;
let result = format_decimal_with_zeros(num, 5, 5);
println!("Original number: {:.5}", num);
println!("Formatted string: {}", result);
}
/*
run:
Original number: 3.14159
Formatted string: 00003.14159
*/
