Compilare: user.cpp: In function ‘void build_suffixArray()’: user.cpp:29:26: warning: suggest parentheses around ‘-’ inside ‘<<’ [-Wparentheses] if(j+(1<<loga-1)<len) ^ user.cpp:30:47: warning: suggest parentheses around ‘-’ inside ‘<<’ [-Wparentheses] l[j].nr2=sa[loga-1][j+(1<<loga-1)]; ^ user.cpp: In function ‘int main()’: user.cpp:53:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("substr.in","r",stdin); ^ user.cpp:54:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("substr.out","w",stdout); ^ user.cpp:55:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n",&len,&k); ^ user.cpp:56:14: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(str); ^ /tmp/ccdevQlg.o: In function `main': user.cpp:(.text.startup+0x72): warning: the `gets' function is dangerous and should not be used.