Compilare: user.cpp: In function ‘void sol()’: user.cpp:28:80: warning: statement has no effect [-Wunused-value] if(G[i].empty()) {int v; v=s[nrs-1]-'0'; v++; f[i]=v; s[nrs]=v+'0'; s[nrs+1]; fout<<v<<" "; } ^ user.cpp:39:84: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] if(strchr(s,c)==NULL) {f[i]=p;fout<<p<<" "; nrs++; s[nrs-1]=c; s[nrs]=NULL;} ^ user.cpp:45:77: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] if(strchr(s,c)==NULL) {f[i]=p;fout<<p<<" "; nrs++; s[nrs-1]=c; s[nrs]=NULL;} ^