> #include <stdio.h>
> void main(){
> int number,c;
> float length,sum;
> scanf("%f",&length);
> while(length!=0.0){sum=0.0;
> if(length<=5.20&&length>=0.01)
> {for(c=2;length>sum;sum=sum+(1.0/c),c++);
>  number=c-2;
>  printf("%d card(s)\n",number);
> }
> scanf("%f",&length);
> }
> }

注意条件