Compilare: main.cpp: In function 'int toposort(std::vector<int>*, int, int*)': main.cpp:19:12: warning: unused variable 'l' [-Wunused-variable] int i, l = 0, length = 1, new_length = 0; ^ main.cpp:19:19: warning: unused variable 'length' [-Wunused-variable] int i, l = 0, length = 1, new_length = 0; ^~~~~~ main.cpp:19:31: warning: unused variable 'new_length' [-Wunused-variable] int i, l = 0, length = 1, new_length = 0; ^~~~~~~~~~ main.cpp:44:16: warning: unused variable 'pp' [-Wunused-variable] struct per pp; ^~ main.cpp:48:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ main.cpp: In function 'int main()': main.cpp:51:9: warning: unused variable 'i' [-Wunused-variable] int i, j, n, m, x, y; ^ main.cpp:51:12: warning: unused variable 'j' [-Wunused-variable] int i, j, n, m, x, y; ^ main.cpp:65:10: warning: unused variable 'ans' [-Wunused-variable] int *ans = (int*)malloc(100 * sizeof(int)); ^~~ main.cpp:55:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.in", "r", stdin); ^ main.cpp:56:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.out", "w", stdout); ^ main.cpp:58:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &n, &m); ^ main.cpp:60:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^