Compilare: user.c: In function ‘main’: user.c:14:4: warning: implicit declaration of function ‘malloc’ [-Wimplicit-function-declaration] buf=(char*)malloc(100); ^ user.c:14:15: warning: incompatible implicit declaration of built-in function ‘malloc’ [enabled by default] buf=(char*)malloc(100); ^ user.c:20:11: warning: format ‘%s’ expects argument of type ‘char *’, but argument 3 has type ‘char **’ [-Wformat=] fscanf(fp_r,"%s",&buf); ^ user.c:21:11: warning: implicit declaration of function ‘strlen’ [-Wimplicit-function-declaration] lg=strlen(buf); ^ user.c:21:14: warning: incompatible implicit declaration of built-in function ‘strlen’ [enabled by default] lg=strlen(buf); ^