血型统计

#include <iostream>#include <iomanip>using namespace std;int main(){  int a=0, b=0, ab=0, o=0;  char blood;  cin>>blood;  while(blood!='X')  {    switch (blood)    {    case 'A' :      a++;      break;    case 'B' :      b++;      break;    case 'C' :      ab++;      break;    case 'O' :      o++;      break;    }  cin>>blood;  }  cout<<"A:"<<a<<endl;  cout<<"B:"<<b<<endl;  cout<<"O:"<<o<<endl;  cout<<"AB:"<<ab<<endl;  return 0;}

输出结果：

学习总结：开始不懂，后来发现，怎么这么简单，忘输break；了