学步园

string str="ab defg";
int i=str.find(' ');
string str1=str.substr(0,i);
cout<<str1;
return 0;

切割字符串
#include <sstream>
#include <string>
#include <iostream>
using namespace std;
int main()
{
        string text = "big|dog|china|sonic|free";
        stringstream ss(text);
        string sub_str;
        while(getline(ss,sub_str,'|')) //以|为间隔分割test的内容
                cout << sub_str << endl;

        return 0;
}
输出如下：
big
dog
china