Compilare: user.cpp: In function ‘int main()’: user.cpp:22:35: warning: format ‘%s’ expects argument of type ‘char*’, but argument 3 has type ‘char (*)[25]’ [-Wformat=] fscanf(f,"%s",&s); ^ user.cpp:23:29: warning: NULL used in arithmetic [-Wpointer-arith] if (s[0]==NULL) {ok=false;break;} ^ user.cpp:27:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i<strlen(s)) {lit=s[i]-'a'; ^ user.cpp:40:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i<strlen(s)) {lit=s[i]-'a'; ^ user.cpp:53:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i<strlen(s)) {lit=s[i]-'a'; ^ user.cpp:67:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i<strlen(s)) {lit=s[i]-'a'; ^ user.cpp:18:8: warning: unused variable ‘j’ [-Wunused-variable] {int i,j,op,lit; ^ user.cpp:20:37: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] while (ok==true) {fscanf(f,"%d",&op); ^ user.cpp:22:36: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%s",&s); ^