c++中统计输入字符的个数经典代码

#include <vector>
#include <list>
#include <algorithm>
#include <iostream>

using namespace std;

int Count( const string &s,char c)
{
 int n=0;
 string::const_iterator i=find(s.begin(),s.end(),c);
 while (i!=s.end()) {
  ++n;
     i=find(i+1,s.end(),c);
 }
 return n;
}

void main()
{
 
 string m="I have a bas";
 int a_count=Count(m,'a');
 cout<<a_count;

}