Compilare: main.c: In function 'main': main.c:88:7: warning: implicit declaration of function 'strlen' [-Wimplicit-function-declaration] if (strlen(c) > 2) ^~~~~~ main.c:88:7: warning: incompatible implicit declaration of built-in function 'strlen' main.c:88:7: note: include '<string.h>' or provide a declaration of 'strlen' main.c:74:2: warning: ignoring return value of 'fgets', declared with attribute warn_unused_result [-Wunused-result] fgets(c, 99998, f); ^~~~~~~~~~~~~~~~~~ main.c:87:3: warning: ignoring return value of 'fgets', declared with attribute warn_unused_result [-Wunused-result] fgets(c, 99998, f); ^~~~~~~~~~~~~~~~~~