UVa 1586 - Molar mass

识别化学式，然后计算总值

 1 #include <cstdio>
 2 #include <iostream>
 3 #include <cstring>
 4 using namespace std;
 5 double a[5]={0,12.01,1.008,16.00,14.01};
 6 char s[105];
 7 int t,len,cnt;
 8 double ans,tmp;
 9 void fuc(){
10     ans=0; cnt=1;
11     for(int i=0;i<len;i++){
12         if(s[i]=='C') tmp=a[1];
13         else if(s[i]=='H') tmp=a[2];
14         else if(s[i]=='O') tmp=a[3];
15         else if(s[i]=='N') tmp=a[4];
16         else {
17             cnt*=(s[i]-'0');
18             while(s[i+1]<='9'&&s[i+1]>='0'){
19                 i++;
20                 cnt*=10;
21                 cnt+=(s[i]-'0');
22             }
23         }
24         if(s[i+1]>'9'||s[i+1]<'0'){
25             ans+=tmp*cnt;
26             cnt=1;
27         }
28     }
29 }
30 int main(){
31     scanf("%d",&t);
32     while(t--){
33         scanf("%s",s);
34         len=strlen(s);
35         fuc();
36         printf("%.3lf\n",ans);
37     }
38 }