#include <stdio.h>
#include <math.h>
/*
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
out - output buffer
out_size - size of output buffer
Example:
num = 3.14159, width = 5, decimals = 5
Output → "00003.14159"
*/
void format_decimal_with_zeros(double num, int width, int decimals,
char *out, int out_size)
{
int integer_part = (int)num;
double fractional_part = num - integer_part;
// Format integer part with leading zeros
char int_str[32];
sprintf(int_str, "%0*d", width, integer_part);
// Format fractional part (starts with "0.xxx")
char frac_str[32];
sprintf(frac_str, "%.*f", decimals, fractional_part);
// Skip the leading "0" before the decimal point
snprintf(out, out_size, "%s%s", int_str, frac_str + 1);
}
int main() {
double num = 3.14159;
char result[64];
format_decimal_with_zeros(num, 5, 5, result, sizeof(result));
printf("Original number: %f\n", num);
printf("Formatted string: %s\n", result);
return 0;
}
/*
run:
Original number: 3.141590
Formatted string: 00003.14159
*/
