Compilare: user.cpp: In function ‘int main()’: user.cpp:5:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("tnia.in","r",stdin); ^ user.cpp:6:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("tnia.out","w",stdout); ^ user.cpp:8:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:10:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&v[i]); ^ user.cpp:13:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&q); ^ user.cpp:15:42: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&c1,&l1,&c2,&l2); ^ user.cpp:49:41: warning: ‘sol2’ may be used uninitialized in this function [-Wmaybe-uninitialized] s=s+(d[sol2-1]-d[sol1]-(sol2-sol1-1)*(l1-1)); ~~~~^~~~~ user.cpp:49:34: warning: ‘sol1’ may be used uninitialized in this function [-Wmaybe-uninitialized] s=s+(d[sol2-1]-d[sol1]-(sol2-sol1-1)*(l1-1)); ~~~~~~^