c++ - Access violation writing location on creation of new array -

i working on homework assignment , instructor class not allow ask questions. demands try figure out on our own have been trying work past week , throwing same error , have no clue why. have done google searches , browsed has similar error , couldn't find solution.

it works fine until after creates new array , user input entered start filling new array, throws :

first-chance exception @ 0x000b517b in 6b.exe: 0xc0000005: access violation writing location 0x00008147. program '[4112] 6b.exe' has exited code 0 (0x0).

#include "stdafx.h" #include <iostream> using namespace std;  int* read_data(int& size){     size++;     return &size;    }  void main(){     int size = 0; // size 0 start     int max = 10; // set max 10 start     float user; //user imputed float number      cout << "start entering numbers.\n sure hit return between each one.\nwhen finished, hit 'q'\n";      float *a = new float [max]; //set first array can deleted , replaced      {         //if array full, make new 1 , replace.         if(size == max){             max = max *2; //double max number             float *b = new float [max]; //create temporary array b              (int = 0; < size; i++){                 b[i] = a[i]; //copy old array temporary             }             delete[] a; //remove old array.             float *a = new float [max]; //create new array new max, same name loop.              //copy new array resume filling             for(int = 0; i< size; i++){                 a[i] = b[i];             }              delete[] b; //remove temporary array free memory.         }          cin >> user; // user inputs number         a[size] = user; //user input         read_data(size); //increase size one.     }while (!cin.fail());      size--; //remove 1 entering of q otherwise throws off count.      if (cin.fail()){         cout << "\n\nyou have finished inputting.\n have imputed " << size << " numbers. \nthe inputed numbers follows:\n";         for(int i=0; < size; i++){             cout << a[i];              if (i == size -1){                 cout << "\n\n";             }             else {                 cout << ", ";             }         }         cout << "\n\n";     }     system("pause");  } 

the instructor wants comments on every line why there many.

if me wonderful.

 delete[] a; //remove old array. 

this deletes a array declared in outer scope of main() function, top.

next line:

 float *a = new float [max];  

this creates new variable named a in inner scope. going forward, think happening original a, declared @ beginning of main() being done other a. original a "hidden", and, such, when scope ends, new array allocated leaked, , original a array pointing unallocated memory.

hillarity ensues.

"the more overthink plumbing, easier stop drain" - scotty, star trek iii.

after allocated new b array, , copied contents of a it, needed was:

 a=b; 

you don't need allocate a array, , copy b, delete b. accomplishes absolutely nothing, , doing inadvertently ended making evil mistake...