c - Calling a function in another function: segmentation fault(core dumped) -

i'm supposed function erases repeated characters in string. here's code:

 #include <stdio.h>  #include <stdlib.h>  #include <string.h>   #define dim 100   char* mystrcpy(char [], char[]);  char* repeticoes(char []);   int main() {  char str1[dim]="john joanne";  printf("%s", repeticoes(str1));   return exit_success; }  char* mystrcpy(char _dest[], char _orig[]) { int i=0; (i=0; _orig[i]!='\n'; i++)     _dest[i]=_orig[i]; _dest[i]='\0'; return _dest; }   char* repeticoes(char _s[]) { int i=0,j=0; char news[dim]={'\0'}; (i=0, j=0; _s[i]!='\0'; i++) {     if(mystrcnt(_s, _s[i])==1)         news[j++]=_s[i]; } news[j]='\0'; mystrcpy(_s, news);  return _s; } 

mystrcpy function created in previous exercise. problem i'm obtaining segmentation fault(core dumped). if try use string library function strcpy program runs ok. problem functions? not declaring/initializing/passing arguments strings correctly?

thanks!

edit: forgot indicate str1.

in function mystrcpy loop -

for (i=0; _orig[i]!='\n'; i++)        //can cause accessing index out of bounds 

why check '\n' , append '\0'later ? once check _orig contain '\n' , understand.

you can run loop till '\0' , copy.