Compilare: user.cpp: In function ‘int main()’: user.cpp:10:15: warning: variable ‘a’ set but not used [-Wunused-but-set-variable] int p, n, a[55][55]; ^ user.cpp:14:9: warning: unused variable ‘m’ [-Wunused-variable] int m=(n*(n+1))/2; ^ user.cpp:7:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pic.in", "r", stdin); ^ user.cpp:8:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pic.out", "w", stdout); ^ user.cpp:11:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n%d", &p, &n); ^ user.cpp:18:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^