Hope it helps

floatToString.cpp

#include <iostream>

using namespace std;
void insertIntIntoCharArr(int num, char arr[], int &pos)
{
	while(num > 0)
	{
		arr[pos++] = num % 10 + 48;
		num /= 10;
	}
}
void floatToString(float num, char arr[], int afterPoint)
{
	int numInt = (int)num;
	
	int pot = 1;
	while(afterPoint--) pot *= 10;
	
	int numFloatPart = (int)(pot * ((float(numInt) ) - num) *-1.0 );
	
	int index = 0;
	
	insertIntIntoCharArr(numFloatPart, arr, index);
	arr[index] = '.'; index++;
	insertIntIntoCharArr(numInt, arr, index);
	
	//backwards
	int l = 0, r = index-1;
	char aux;
	
	while(l < r)
	{
		aux = arr[l];
		arr[l] = arr[r];
		arr[r] = aux;
		l++; r--;
	}
}


int main()
{
	char arr[10];
	floatToString(123.524, arr, 3);
	cout << arr << endl;
	return 0;
}