Compilare: user.cpp: In function ‘void build(int, int, int)’: user.cpp:15:22: warning: format ‘%s’ expects argument of type ‘char*’, but argument 2 has type ‘char (*)[20]’ [-Wformat=] scanf("%s",&s); ^ user.cpp:15:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s",&s); ^ user.cpp: In function ‘int main()’: user.cpp:36:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("saracsaurege.in","r",stdin); ^ user.cpp:37:44: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("saracsaurege.out","w",stdout); ^ user.cpp:38:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:41:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&a,&b); ^