c++ - Passing 2D array and vector of string as argument to function -

i have written 2 function in passing vector of string particular function (printstringvector) print content , in second function, passing array of pointers print content.the first function working fine second 1 giving error below code.

#include <cmath> #include <stdlib.h> #include <cstdio> #include <string> #include <vector> #include <iostream> #include <algorithm> using namespace std; int n;  void printstringvector(vector<string> & v){       for(int i=0;i<v.size();i++){ cout<<v[i]<<endl;}  }   void printstringarray(const char *arr[n]){      for(int i=0;i<n;i++){ cout<<arr[i]<<endl;}    }  int main() {      vector<string>  vec;                         cin>>n;     const char *arr[n];      for(int i=0;i<n;i++){         string str;         cin>>str;          vec.push_back(str);         arr[i]=str.c_str();     }      printstringvector(vec);     printstringarray(arr);       return 0; } 

errors:

        vinod@vinod-inspiron-3537:~/documents/hackerrank$ g++       passing_vector_of_string_or_passing_2d_array.cpp          passing_vector_of_string_or_passing_2d_array.cpp:17:35: error: expected ‘,’ or ‘...’ before ‘arr’         void printstringarray(const char* arr[n]){                                            ^         passing_vector_of_string_or_passing_2d_array.cpp: in function ‘void printstringarray(const char*)’:         passing_vector_of_string_or_passing_2d_array.cpp:19:33: error: ‘arr’ not declared in scope         for(int i=0;i<n;i++){ cout<<arr[i]<<endl;}                                          ^         passing_vector_of_string_or_passing_2d_array.cpp: in function ‘int main()’:         passing_vector_of_string_or_passing_2d_array.cpp:40:25: error: cannot convert ‘const char**’ ‘const char*’ argument ‘1’ ‘void printstringarray(const char*)’         printstringarray(arr); 

const char *arr[n] 

this not valid declaration (unless n constant expression). c++ has no variable length arrays.

"but works me inside main!'

that's because g++ implements extension c++. extension not seem compatible c variable-length arrays, , buggy. don't use it.

"but how can have comparable functionality?"

use std::vector. not use pointers, new[] , delete[] unless know extremely why need these low-level primitives.