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C++ memory leak in recursion


C++ memory leak in recursion

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C++ memory leak in recursion
Tag : cpp , By : NeedOptic
Date : November 24 2020, 01:01 AM

hop of those help? Replace ** with vectors and avoid using calloc, malloc, new and delete.
std::vector< std::vector<int> > result = ....
typedef std::vector< std::vector<int> >  Matrix;

Matrix  matrixmul(const Matrix& A, const Matrix& B, int n) {
  Matrix result(n);
  for (int i = 0; i < n; ++i)
    result[i] = std::vector<int>(n);

  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < n; ++j) {
      int sum = 0;
      for (int k = 0; k < n; ++k) {
        sum += A[i][k] * B[k][j];
      }
     result[i][j] = sum;
    }
  }
  return result;
}

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Recursion with pointer and memory leak


Tag : cpp , By : Yolanda N. Ceron
Date : March 29 2020, 07:55 AM
will be helpful for those in need
"Could any one point out if following code can have a memory leak when its executed?"
char *temp_string = new char[100];  // first assignment

[...]

if (number>=1000)
{   
[...]
    temp_string = convert_number(number,places); 

Irrefutable pattern does not leak memory in recursion, but why?


Tag : haskell , By : johntynan
Date : March 29 2020, 07:55 AM
I think the issue was by ths following , Let me first answer why mapAndSome can work good at all: What you see is (very likely) the effect of an optimization described by Philip Wadler in “Fixing some space leaks with a garbage collector”. Short summary: If the garbage collector sees a thunk of the form fst x and x is already evaluated to the tuple constructor, e.g. (y,z), it will replace fst x by y, possibly freeing up z if it is not referenced anywhere else.
In your code, the s' will, once the result of go is evaluated to a tuple and after one round of GCing, not keep a reference to the tuple but will be replaced by the accumulated parameter.
foo_r2eT :: ([Type.Integer], Type.Integer)

foo_r2eT =
  case $wgo_r2eP mapAndSum1 lvl2_r2eS
  of _ { (# ww1_s2d7, ww2_s2d8 #) ->
  (ww1_s2d7, ww2_s2d8)
  }
case eqString ds_dyA lvl18_r2fd of _ {
  False -> $wa_s2da new_s_a14o;
  True ->
    case ds1_dyB of _ {
      [] ->
        case Handle.Text.hPutStr2
               Handle.FD.stdout lvl17_r2fc True new_s_a14o
        of _ { (# new_s1_X15h, _ #) ->
        Handle.Text.hPutStr2
          Handle.FD.stdout lvl16_r2fb True new_s1_X15h
        };
      : ipv_sIs ipv1_sIt -> $wa_s2da new_s_a14o
    }
lvl17_r2fc :: String
[GblId]
lvl17_r2fc =
  case foo_r2eT of _ { (xs_Xqp, s_Xq9) ->
  $w$cshowsPrec
    0
    (Data.List.sum_sum' xs_Xqp Data.List.genericDrop2)
    ([] @ Char)
  }

lvl16_r2fb :: String
[GblId]
lvl16_r2fb =
  case foo_r2eT of _ { (xs_apS, s_Xqp) ->
  $w$cshowsPrec 0 s_Xqp ([] @ Char)
  }
            case eqString ds_dyA lvl8_r2f1 of _ {
              False -> $wa2_s2dI w3_s2cF;
              True ->
                case ds1_dyB of _ {
                  [] ->
                    Handle.Text.hPutStr2
                      Handle.FD.stdout lvl7_r2f0 True w3_s2cF;
                  : ipv_sHg ipv1_sHh -> $wa2_s2dI w3_s2cF
                }
            } } in
lvl7_r2f0 :: String
[GblId]
lvl7_r2f0 =
  case foo_r2eT of _ { (x_af6, y_af7) ->
  show_tuple
    (:
       @ ShowS
       (let {
          w2_a2bY [Dmd=Just L] :: Type.Integer

          w2_a2bY = lgo_r2eU mapAndSum1 x_af6 } in
        \ (w3_a2bZ :: String) ->
          $w$cshowsPrec 0 w2_a2bY w3_a2bZ)
       (:
          @ ShowS
          (\ (w2_a2bZ :: String) ->
             $w$cshowsPrec 0 y_af7 w2_a2bZ)
          ([] @ ShowS)))
    ([] @ Char)
  }
 case eqString ds_dyA (unpackCString# "bad?")
                 of _ {
                   False -> fail2_dyN realWorld#;
                   True ->
                     case ds1_dyB of _ {
                       [] ->
                         $
                           @ (Type.Integer, Type.Integer)
                           @ (IO ())
                           (System.IO.print
                              @ (Type.Integer, Type.Integer) $dShow_rzk)
                           ($
                              @ ([Type.Integer], Type.Integer)
                              @ (Type.Integer, Type.Integer)
                              (Control.Arrow.first
                                 @ (->)
                                 Control.Arrow.$fArrow(->)
                                 @ [Type.Integer]
                                 @ Type.Integer
                                 @ Type.Integer
                                 sum'_rzm)
                              foo_rzl);
                       : ipv_szd ipv1_sze -> fail2_dyN realWorld#
                     }
                 } } in
w_r2f2 :: Type.Integer

w_r2f2 =
  case foo_r2eT of _ { (x_aI1, y_aI2) ->
  lgo_r2eU mapAndSum1 x_aI1
  }

lvl9_r2f3 :: String -> String
[GblId, Arity=1]
lvl9_r2f3 =
  \ (w2_a2bZ :: String) ->
    $w$cshowsPrec 0 w_r2f2 w2_a2bZ

w1_r2f4 :: Type.Integer

w1_r2f4 = case foo_r2eT of _ { (x_aI6, y_aI7) -> y_aI7 }

lvl10_r2f5 :: String -> String
[GblId, Arity=1]
lvl10_r2f5 =
  \ (w2_a2bZ :: String) ->
    $w$cshowsPrec 0 w1_r2f4 w2_a2bZ

lvl11_r2f6 :: [ShowS]
[GblId]
lvl11_r2f6 =
  :
    @ ShowS lvl10_r2f5 ([] @ ShowS)

lvl12_r2f7 :: [ShowS]
[GblId]
lvl12_r2f7 = : @ ShowS lvl9_r2f3 lvl11_r2f6

lvl13_r2f8 :: ShowS
[GblId]
lvl13_r2f8 = show_tuple lvl12_r2f7

lvl14_r2f9 :: String
[GblId]
lvl14_r2f9 = lvl13_r2f8 ([] @ Char)

Memory leak in recursion


Tag : cpp , By : user157064
Date : March 29 2020, 07:55 AM
around this issue Compiling your code and running it in valgrind produces this as the first occurrence of your memory leak:
==20797== Invalid write of size 4
==20797==    at 0x400BA0: Sort_And_count_split_Inv(int*, int, int, int) (in /home/test/TestCPP)
==20797==    by 0x4009D4: Sort_And_count(int*, int, int) (in /home/test/TestCPP)
==20797==    by 0x4009BC: Sort_And_count(int*, int, int) (in /home/test/TestCPP)
==20797==    by 0x4009A2: Sort_And_count(int*, int, int) (in /home/test/TestCPP)
==20797==    by 0x400921: main (in /home/test/TestCPP)
==20797==  Address 0x5a1d0ec is 4 bytes after a block of size 8 alloc'd
==20797==    at 0x4C2B800: operator new[](unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==20797==    by 0x400AE8: Sort_And_count_split_Inv(int*, int, int, int) (in /home/test/TestCPP)
==20797==    by 0x4009D4: Sort_And_count(int*, int, int) (in /home/test/TestCPP)
==20797==    by 0x4009BC: Sort_And_count(int*, int, int) (in /home/test/TestCPP)
==20797==    by 0x4009A2: Sort_And_count(int*, int, int) (in /home/test/TestCPP)
==20797==    by 0x400921: main (in /home/test/TestCPP)
tmp[k] = a[i];

Memory leak while using tail-recursion


Tag : javascript , By : WellBeing
Date : March 29 2020, 07:55 AM
I hope this helps you . I think as of right now, the answer is "the intermediate variable should be released, but it won't be".
ES6 does talk about tail-position calls and even requires optimization:

memory leak in php with recursion


Tag : php , By : IanM
Date : March 29 2020, 07:55 AM
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