Compilare: user.cpp: In function ‘int main()’: user.cpp:47:15: warning: unused variable ‘j’ [-Wunused-variable] int m, i, j; ^ user.cpp:45:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("tunel.in", "r", stdin); ^ user.cpp:46:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("tunel.out", "w", stdout); ^ user.cpp:49:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:51:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &x[i], &y[i], &c[i]); ^ user.cpp: In function ‘void gauss()’: user.cpp:32:24: warning: ‘k’ may be used uninitialized in this function [-Wmaybe-uninitialized] swapLines(i, k); ^