字符串中1的个数

 

 1 #include<string>
 2 #include<iostream>
 3 using namespace std;
 4 
 5 int main()
 6 {
 7     string str="1hj1jk11jnk111jk1";
 8     int num=0;
 9     //cin>>str;
10     for(unsigned int i=0;i<str.size();i++)
11     {
12         if(str.at(i)=='1')
13             num++;
14     }
15     cout<<num<<endl;
16     return 0;
17 }