Compilare: user.cpp: In function ‘void rezolva(char*, float&, float&, int&, char*)’: user.cpp:22:20: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] {p[l-1]=NULL; ^ user.cpp: In function ‘int main()’: user.cpp:61:11: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] *p=NULL; ^ user.cpp:45:25: warning: unused variable ‘s2’ [-Wunused-variable] char s[300],s1[300],s2[300],*p,s3[300]; ^