C/C++ counting the number of decimals?

Question

Lets say that input from the user is a decimal number, ex. 5.2155 (having 4 decimal digits). It can be stored freely (int,double) etc.

Is there any

Answer 1

char* fractpart(double f)
 {
    int intary={1,2,3,4,5,6,7,8,9,0};
    char charary={'1','2','3','4','5','6','7','8','9','0'};
    int count=0,x,y;
    f=f-(int)f;
           while(f<=1)
           {
                     f=f*10;
                     for(y=0;y<10;y++)
                         {
                                if((int)f==intary[y])
                                 {
                                           chrstr[count]=charary[y];
                                           break;
                                 }
                         }
    f=f-(int)f;
    if(f<=0.01 || count==4)
   break;
   if(f<0)
   f=-f;
   count++;
    }
     return(chrstr);
    }