#include <iostream>
#include <iomanip>
#include <sstream>
using std::stringstream;
/*
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"
*/
std::string format_decimal_with_zeros(double num, int width, int decimals)
{
// Split into integer and fractional parts
int integer_part = static_cast<int>(num);
double fractional_part = num - integer_part;
// Convert integer part with leading zeros
stringstream int_ss;
int_ss << std::setw(width) << std::setfill('0') << integer_part;
std::string int_str = int_ss.str();
// Convert fractional part (starts with "0.xxx")
stringstream frac_ss;
frac_ss << std::fixed << std::setprecision(decimals) << fractional_part;
std::string frac_str = frac_ss.str();
// Remove the leading "0" before the decimal point
return int_str + frac_str.substr(1);
}
int main() {
double num = 3.14159;
std::string result = format_decimal_with_zeros(num, 5, 5);
std::cout << "Original number: " << num << std::endl;
std::cout << "Formatted string: " << result << std::endl;
}
/*
run:
Original number: 3.14159
Formatted string: 00003.14159
*/
