Find a string combination

For example, the combination of "abc" strings is a, B, c, AB, ac, bc, and abc. Here I use two methods: Bit operation:

# Include <iostream> # include <vector> using namespace std; // bit operation algorithm void main () {char * data = "abcd"; int length = strlen (data ); int last = (1 <length)-1; cout <last <endl; int I; for (I = 1; I <= last; I ++) {int currentIndex = length-1; while (currentIndex> = 0) {if (I & (1 <currentIndex) {cout <data [length-currentIndex-1];} -- currentIndex;} cout <endl ;}}

 

Recursive operation:

void algorithm(char* data,int num,vector<char>& result)  {      if(!num)      {          vector<char>::iterator it=result.begin();          for(it;it!=result.end();++it)          {              cout<<*it;          }          cout<<endl;          return;      }      if(*data=='\0')          return;      result.push_back(*data);      algorithm(data+1,num-1,result);      result.pop_back();      algorithm(data+1,num,result);  }    void main()  {      char* data="abcd";      int length=strlen(data);      vector<char> result;      int i;      for(i=1;i<=length;i++)      {          algorithm(data,i,result);      }  }