急 求此道编程题的 完整编码 需要用C语言编写 急需㰠࿾谢谢

#include
#include
int main()
{
char a[];
int i,n;
float s;
gets(a);
do
{a[i]=getchar();i++;}while(a[i-1]!='\n');
n=i-1;
for(i=0;i switch(a[i])
{
case 'C':a[i]=12.01;
if(!(a[i+1]>='1'&&a[i+1]<='9'))
s+=12.1;
break;
case 'H':a[i]=1.008;
if(!(a[i+1]>='1'&&a[i+1]<='9'))
s+=1.008;
break;
case 'O':a[i]=16.00;
if(!(a[i+1]>='1'&&a[i+1]<='9'))
s+=16.00;
break;
case 'N':a[i]=14.01;
if(!(a[i+1]>='1'&&a[i+1]<='9'))
s+=14.01;
break;