Compilare: user.c: In function ‘main’: user.c:66:9: warning: format ‘%s’ expects argument of type ‘char *’, but argument 3 has type ‘char (*)[30]’ [-Wformat=] fscanf(f,"%s",&sir); ^ user.c:73:17: warning: implicit declaration of function ‘isdigit’ [-Wimplicit-function-declaration] while(isdigit(sir[j])) ^ user.c: In function ‘pop’: user.c:45:5: warning: control reaches end of non-void function [-Wreturn-type] } //sf pop_back ^ user.c: In function ‘main’: user.c:62:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&n); ^ user.c:66:15: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%s",&sir); ^