A function printing float to char* buffer without using %f. Excellent for arduino projects purpose. Fully SIGSEGV-prone. Enjoy!

printfloat.c

#include <stdio.h>

/// Prints float to buffer without using %f (for microcontrollers purpose)
///
/// Usage:
///     char buffer[20];
///     printFloatToBuffer(buffer, 20, -3.1415, 3);
///     printf("%s", buffer);
///
void printFloatToBuffer(char *buffer, size_t bufferSize, float val, unsigned int precision) {
   int significant = (int)val;
   if (precision == 0) {
     // print significant w/o separator
     snprintf(buffer, bufferSize, "%d", significant);
     return;
   }

   float frac;
   if(val >= 0)
       frac = (val - significant);
   else
       frac = (significant - val);
   for (unsigned int i = 0; i < precision; ++i)
     frac *= 10;

   char format[10];
   // include leading zeros for fraction (case 23.002 => frac == 2)
   snprintf(format, 10, "%%d.%%0%dd", precision);
   snprintf(buffer, bufferSize, format, significant, (unsigned int)frac);
}

int main() {
    char buf[50];
    printFloatToBuffer(buf, 6, -21.6, 1);
    printf("%s\n", buf);
    return 0;
}