c - Passing array to function results in segmentation fault (core dumped) -

i trying build quicksort function results in segmentation fault (core dumped). having read error sure have stray pointer can't spot it. used valgrind me debug , comment lines valgrind told me in following piece of code:

#include <stdio.h> #include <assert.h>    int partition(int *a,int l, int h, int pivot)  {   l++;   while(l <= h && a[l] < a[pivot])   {     l++;   }   while(a[h] >= a[pivot])   { //conditional jump depends on uninitialised value here     h--;   }   if(l < h)    {     int tmp = a[l];     a[l] = a[h];     a[h] = tmp;     partition(a,l,h,pivot);    }    else    {     int tmp = a[pivot];     a[pivot] = a[h];     a[h] = tmp;     return h;   }  return -1; }     void quicksort(int *a, int low, int high)  {   //base case.   if(low - high == 0){     return;   }   //just 2 elements in array sorted   if(low - high == -1)    {     if (a[low] < a[high])       {       int tmp = a[low];       a[low] = a[high];       a[high] = tmp;      }      else     {       return;     }   }   else   {   //the actual algorithm   int pivot = a[low];   int j = partition(a,low,high,low); //caused (valgrind)   int tmp = pivot;   a[low] = a[j];   a[j] = tmp;   quicksort(a,0,j-1); //and (valgrind)   quicksort(a,j+1,high);   } }     int main(int argc, char *argv[])   {   int a[] = {5,1,5,3,4,1};   quicksort(a,0,5);   int n = 0;   while(n < 6)    {     printf("index %d %d\n",n,a[n]);     n++;   }     return 0; } 

any insight appreciated

here output valgrind

==4698== memcheck, memory error detector ==4698== copyright (c) 2002-2013, , gnu gpl'd, julian seward et al. ==4698== using valgrind-3.10.1 , libvex; rerun -h copyright info ==4698== command: ./quicksort ==4698==  ==4698== conditional jump or move depends on uninitialised value(s) ==4698==    @ 0x4005b8: partition (quicksort.c:9) ==4698==    0x40079e: quicksort (quicksort.c:46) ==4698==    0x400803: quicksort (quicksort.c:50) ==4698==    0x40081a: quicksort (quicksort.c:51) ==4698==    0x400803: quicksort (quicksort.c:50) ==4698==    0x400803: quicksort (quicksort.c:50) ==4698==    0x40086b: main (quicksort.c:61) ==4698==  ==4698== conditional jump or move depends on uninitialised value(s) ==4698==    @ 0x4005b8: partition (quicksort.c:9) ==4698==    0x40079e: quicksort (quicksort.c:46) ==4698==    0x400803: quicksort (quicksort.c:50) ==4698==    0x400803: quicksort (quicksort.c:50) ==4698==    0x40081a: quicksort (quicksort.c:51) ==4698==    0x400803: quicksort (quicksort.c:50) ==4698==    0x400803: quicksort (quicksort.c:50) ==4698==    0x40086b: main (quicksort.c:61) ==4698==  ==4698== stack overflow in thread 1: can't grow stack 0xffe801ff8 ==4698==  ==4698== process terminating default action of signal 11 (sigsegv) ==4698==  access not within mapped region @ address 0xffe801ff8 ==4698==    @ 0x400535: partition (quicksort.c:4) ==4698==  if believe happened result of stack ==4698==  overflow in program's main thread (unlikely ==4698==  possible), can try increase size of ==4698==  main thread stack using --main-stacksize= flag. ==4698==  main thread stack size used in run 8388608. ==4698== stack overflow in thread 1: can't grow stack 0xffe801fd8 ==4698==  ==4698== process terminating default action of signal 11 (sigsegv) ==4698==  access not within mapped region @ address 0xffe801fd8 ==4698==    @ 0x4a256a5: _vgnu_freeres (vg_preloaded.c:58) ==4698==  if believe happened result of stack ==4698==  overflow in program's main thread (unlikely ==4698==  possible), can try increase size of ==4698==  main thread stack using --main-stacksize= flag. ==4698==  main thread stack size used in run 8388608. ==4698==  ==4698== heap summary: ==4698==     in use @ exit: 0 bytes in 0 blocks ==4698==   total heap usage: 0 allocs, 0 frees, 0 bytes allocated ==4698==  ==4698== heap blocks freed -- no leaks possible ==4698==  ==4698== counts of detected , suppressed errors, rerun with: -v ==4698== use --track-origins=yes see uninitialised values come ==4698== error summary: 14552 errors 2 contexts (suppressed: 0 0) segmentation fault (core dumped) 

the problem fact if-else statement @ bottom decided whether enter recursion or return index threw small bug wasn't able see.

if condition true function entered recursion once returned, function finished if-else statement , returned -1 went ahead , put index. threw segmentation fault error