深搜 string::substr

#include 
//给出中序和后序
//求先序



using namespace std;
void b(string in,string af)
{
    if(in.size()>0)
    {
        char ch=af[af.size()-1];
        cout<>in>>af;
    b(in,af);
    cout< 
// string::substr
#include 
#include 
using namespace std;

int main ()
{
string str="We think in generalities, but we live in details.";
// (quoting Alfred N. Whitehead)
string str2 = str.substr (3,5); // "think"
size_t pos = str.find("live"); // position of "live" in str
string str3 = str.substr (pos); // get from "live" to the end
cout << str2 << ' ' << str3 << 'n';
return 0;
}
 
//这些毒操作不比毒鸡汤有意思多了
//到晚上了就爱这些毒里毒气的东西