#include<stdio.h>
int main()
{
char c;
double k,m=0,count=0;
scanf("%c",&c);
while(c!='\n')
{
if(c=='C') k=12.01;
if(c=='H') k=1.008;
if(c=='O') k=16.00;
if(c=='N') k=14.01;
scanf("%c",&c);
if((c>='0')&&(c<='9'))
count=0;
else count=1;
while((c>='0')&&(c<='9'))
{
count=count*10+(c-'0');
scanf("%c",&c);
}
m=m+count*k;
}
printf("%.3lf\n",m);
}
在倒数第七行的(c-’0‘)是什么意思?