Thread: Double to String

hi,
how to convert the DOUBLE date into a string without using some certain function of the library?
I need your code(name.c)
thx in advance.
happy new year!

but "sprintf""snprintf""fprintf"are all functions of the library.

I am confesed by my own code:
When I entered the double date:4545.6767.the output is 4545.676699999999999.Why?what should I do ?

Code:

#include <stdio.h>
#include <string.h>
#define Array_MaxValue 17 


char *MY_DoubleToChar(double db,char *db_str)
{
    int DecP=1,loop;
    double _db;
    int db_arr[Array_MaxValue];
    
    if(db>=0.0)
    {
        while(db>=10.0)
        {
            DecP++;
            db/=10;
        }
        for(loop=0;loop<17;loop++)
        {
            if(loop==DecP)
            {
                db_arr[loop]=-2;
                continue;
            }
            db_arr[loop]=(int)db;
            db-=db_arr[loop]; 
            db*=10.0;
        }
        for(loop=0;loop<17;loop++)
            db_str[loop]=db_arr[loop]+48; 
        return(db_str);
    }
    else
    {
        _db=-db;
        while(_db>=10.0)
        {
            DecP++;
            _db/=10;
        }
        for(loop=0;loop<17;loop++)
        {
            if(loop==DecP)
            {
                db_arr[loop]=-2;
                continue;
            }
            db_arr[loop]=(int)(_db);
            _db-=db_arr[loop];
            _db*=10.0;
        }
        for(loop=0;loop<17;loop++)
            db_str[loop]=db_arr[loop]+48;  
        return(db_str);
    } 
}

int main()
{
    const double i;
    char *str;
    char *sign;
    str=(char *)malloc(sizeof(char)*Array_MaxValue);
    sign=(char *)malloc(sizeof(char));
    printf("enter the DOUBLE date:\n");
    scanf("%lf",&i);
    if(i<0.0)
    {
        *sign='-';
        printf("%c",*sign);
        printf("%s",MY_DoubleToChar(i,str));
    }
    else
        printf("%s",MY_DoubleToChar(i,str));
    free(str);
    getch();
    return 0;
}