Compilare: main.c: In function 'PushBack': main.c:45:37: warning: implicit declaration of function 'malloc' [-Wimplicit-function-declaration] struct Queue* newElement = (Queue*)malloc(sizeof(Queue)); ^~~~~~ main.c:45:37: warning: incompatible implicit declaration of built-in function 'malloc' main.c:45:37: note: include '<stdlib.h>' or provide a declaration of 'malloc' main.c: In function 'PopFront': main.c:56:2: warning: implicit declaration of function 'free' [-Wimplicit-function-declaration] free(firstElement); ^~~~ main.c:56:2: warning: incompatible implicit declaration of built-in function 'free' main.c:56:2: note: include '<stdlib.h>' or provide a declaration of 'free' main.c: In function 'Lee': main.c:64:25: warning: incompatible implicit declaration of built-in function 'malloc' firstElement = (Queue*)malloc(sizeof(Queue)); ^~~~~~ main.c:64:25: note: include '<stdlib.h>' or provide a declaration of 'malloc' main.c: In function 'main': main.c:116:2: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d %d", &n, &m); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:121:3: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d %d", &line, &column); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:125:2: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d %d %d %d", &line1, &column1, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ &line2, &column2); ~~~~~~~~~~~~~~~~~