Compilare: main.c: In function 'main': main.c:139:2: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("cameras.in", "r", stdin); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:140:2: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("cameras.out", "w", stdout); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:147:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%i%i%i", &graph.nodeCount, &edgeCount, &cameraNodeCount); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:151:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%i", &nodeIndex); ^~~~~~~~~~~~~~~~~~~~~~~ main.c:156:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%lf%lf", &maxSpeed, &speedLimit); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:161:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%i%i%lf", &fromIndex, &toIndex, &length); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~