Compilare: user.c: In function ‘main’: user.c:41:5: warning: implicit declaration of function ‘strlen’ [-Wimplicit-function-declaration] len = strlen(sir); ^ user.c:41:11: warning: incompatible implicit declaration of built-in function ‘strlen’ [enabled by default] len = strlen(sir); ^ user.c:38:9: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf( in, "%d ", &t ); ^ user.c:40:10: warning: ignoring return value of ‘fgets’, declared with attribute warn_unused_result [-Wunused-result] fgets( sir, MAXL + 1, in ); ^