Compilare: user.c: In function ‘main’: user.c:14:1: warning: implicit declaration of function ‘isdigit’ [-Wimplicit-function-declaration] while(isdigit(ch=fgetc(file1) || isalpha(ch))){ ^ user.c:14:1: warning: implicit declaration of function ‘isalpha’ [-Wimplicit-function-declaration] user.c:6:30: warning: unused variable ‘len’ [-Wunused-variable] long long B, K, i, result=0, len, digit, ch; ^ user.c:6:17: warning: unused variable ‘i’ [-Wunused-variable] long long B, K, i, result=0, len, digit, ch; ^ user.c:11:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%lld %lld", &B, &K); ^