reading files in a directory C++ -

i'm reading files in directory , passing function, think i'm doing in wrong way, not able figure out.

here code first reads files in folder , send function further operations.

#include <dirent.h> #include <stdio.h> #include <vector> #include <string> #include <iostream> using namespace std; std::vector<std::string> filename;   int main(void)  {   dir           *d;  struct dirent *dir;  vector<string> filelist;  int i=0;  d = opendir("files");  if (d)  {  while ((dir = readdir(d)) != null)  {  i++;  filelist.push_back(dir->d_name);   }  for(int i=0;i<filelist.size();i++) {   cout<<filelist[i]<<endl;   dosomething(filelist[i]);  }  closedir(d);   }   return(0);  }   int dosomething(filename) {  //do  }  

error

main.cpp: in function ‘int main()’: main.cpp:29:28: error: ‘dosomething’ not declared in scope  dosomething(filelist[i]);                         ^ main.cpp: @ global scope: main.cpp:37:26: error: cannot convert       ‘std::vector<std::basic_string<char> >’ ‘int’ in initialization int dosomething(filename) {                       ^ main.cpp:37:28: error: expected ‘,’ or ‘;’ before ‘{’ token int dosomething(filename) {                         ^ 

since dosomething function defined after main, not visible, causes first error. correct way @ least declare function first:

int dosomething(); //declaration  int main() {     dosomething(); //now function declared  }  //definition int dosomething() { } 

now, second , third errors emited because didn't include filename parameter's type in function definition. based on code, should string:

int dosomething(string filename) { } 

i noticed that, while function returns int, not using it's returned value. nevertheless, don't forget return dosomething, otherwise cause undefined behavior.