sorting - C++ Insertion Sort: error when passing values between functions -

so i'm coding program class, in c++, ask user input size of array, , numbers inside of it. asks user if wish have sorted in ascending, or descending order.

i have tested each of sorting algorithms individually, , both seem work flawlessly, however, when combine them in sortarr function , pass values entered user main function, monstrous error cant decipher. know problem program is?

#include <iostream> #include <stdio.h> using namespace std;  void sortarr(bool order, int size) {     int imax;     int max;     int arr[size];      if (order == true)     {         (int = size - 1; > 0; i--)         {             max = arr[0];             imax = i;              (int j = 0; j < i; j++)             {                 if (arr[j] > arr[imax])                 {                     max = arr[j];                     imax = j;                 }             }              if (imax != i)             {                 int temp = arr[i];                  arr[i] = arr[imax];                 arr[imax] = temp;             }         }     }      else if (order == false)     {         (int = 0; < size; i++)         {             max = arr[0];             imax = i;              (int j = size - 1; j > i; j--)             {                 if (arr[j] > arr[imax])                 {                     max = arr[j];                     imax = j;                 }             }              if (imax != i)             {                 int temp = arr[i];                  arr[i] = arr[imax];                 arr[imax] = temp;             }         }     } }  int main() {     int size;     int a;     bool order;     string output;      cout << "enter size of array: ";     cin >> size;     if (size < 0)     {         cout << "error: entered incorrect value array size!" << endl;         return 1;     }      int arr[size];      cout << "enter numbers in array, seperated space, , press enter: ";     (int = 0; < size; i++)     {         scanf("%d", &arr[i]);     }      cout << "sort in ascending (0) or descending (1) order? ";     cin >> a;     if (a == 0)     {         order = true;         cout << "this sorted array in ascending order: ";     }     else if (a == 1)     {         order = false;         cout << "this sorted array in descening order: ";     }      output = sortarr(order, size);     cout << output << endl;      return 0; }  cout << "sort in ascending (0) or descending (1) order? "; cin >> a; if(a == 0){     order = true;     cout << "this sorted array in ascending order: "; } else if(a == 1) {     order = false;     cout << "this sorted array in descening order: "; }  output = sortarr(order, size); cout << output << endl;  return 0; } 

the error code i'm receiving this:

sortarray1.cpp: in function 'int main()': sortarray1.cpp:84:9: error: no match 'operator=' (operand types 'std::string {aka std::basic_string<char>}' , 'void')   output = sortarr(order, size);          ^ sortarray1.cpp:84:9: note: candidates are: in file included /usr/include/c++/4.8/string:52:0,                  /usr/include/c++/4.8/bits/locale_classes.h:40,                  /usr/include/c++/4.8/bits/ios_base.h:41,                  /usr/include/c++/4.8/ios:42,                  /usr/include/c++/4.8/ostream:38,                  /usr/include/c++/4.8/iostream:39,                  sortarray1.cpp:1: /usr/include/c++/4.8/bits/basic_string.h:546:7: note: std::basic_string<_chart, _traits, _alloc>& std::basic_string<_chart, _traits, _alloc>::operator=(const std::basic_string<_chart, _traits, _alloc>&) [with _chart = char; _traits = std::char_traits<char>; _alloc = std::allocator<char>]        operator=(const basic_string& __str)        ^ /usr/include/c++/4.8/bits/basic_string.h:546:7: note:   no known conversion argument 1 'void' 'const std::basic_string<char>&' /usr/include/c++/4.8/bits/basic_string.h:554:7: note: std::basic_string<_chart, _traits, _alloc>& std::basic_string<_chart, _traits, _alloc>::operator=(const _chart*) [with _chart = char; _traits = std::char_traits<char>; _alloc = std::allocator<char>]        operator=(const _chart* __s)        ^ /usr/include/c++/4.8/bits/basic_string.h:554:7: note:   no known conversion argument 1 'void' 'const char*' /usr/include/c++/4.8/bits/basic_string.h:565:7: note: std::basic_string<_chart, _traits, _alloc>& std::basic_string<_chart, _traits, _alloc>::operator=(_chart) [with _chart = char; _traits = std::char_traits<char>; _alloc = std::allocator<char>]        operator=(_chart __c)        ^ /usr/include/c++/4.8/bits/basic_string.h:565:7: note:   no known conversion argument 1 'void' 'char' 

you have 2 variables named "arr": 1 in main , 1 in sortarr.

you're reading 1 in main , sorting 1 in sortarr (which uninitialised, program undefined).

pass array parameter:

void sortarr(bool order, int arr[], int size){ 

there's issue of attempting assign non-existent return value (void) of sortarr std::string.
don't that.

call function this:

sortarr(order, arr, size); 

(int arr[size]; relying on g++ extension – variable length arrays – non-standard. consider using std::vector. it's been around couple of decades , nothing fear more.)