Compilare: user.cpp: In function ‘void ec(char*, int&, int&)’: user.cpp:197:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<strlen(s)){ ^ user.cpp:221:29: warning: operation on ‘nr’ may be undefined [-Wsequence-point] nr=nr=r*semn; ^ user.cpp: In function ‘int main()’: user.cpp:252:11: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] *p=NULL; ^ user.cpp: In function ‘void ec(char*, int&, int&)’: user.cpp:217:22: warning: ‘semn’ may be used uninitialized in this function [-Wmaybe-uninitialized] x=x+r*semn; ^