friends.cpp: In function 'int main()':
friends.cpp:32:20: warning: format '%s' expects argument of type 'char*', but argument 2 has type 'char (*)[2000010]' [-Wformat=]
scanf(" %s ", &str);
~~~~^
friends.cpp:31:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d", &n_);
~~~~~^~~~~~~~~~~
friends.cpp:32:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf(" %s ", &str);
~~~~~^~~~~~~~~~~~~~
friends.cpp: In function 'int verif(char*, char*)':
friends.cpp:26:32: warning: 'mini' may be used uninitialized in this function [-Wmaybe-uninitialized]
if( (str2[mini]==str2[mini-1] && mini>=1) || (str2[mini]==str2[mini+1] && mini<=n-1) ) return 2;
~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~