Compilare: user.cpp: In function ‘void quicksort(int, int)’: user.cpp:37:11: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(v[i]==x) ^ user.cpp: In function ‘void gen()’: user.cpp:48:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("file.in", "w", stdout); ^ user.cpp: In function ‘int main()’: user.cpp:58:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("invsort.in", "r", stdin); ^ user.cpp:59:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("invsort.out", "w", stdout); ^ user.cpp:61:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:62:44: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(int i=1;i<=n;i++) scanf("%d",&v[i]); ^