Compilare: main.cpp: In function 'int main()': main.cpp:18:10: warning: converting to non-pointer type 'char' from NULL [-Wconversion-null] s[n]=NULL; ^~~~ main.cpp:19:21: warning: converting to non-pointer type 'char' from NULL [-Wconversion-null] s2[0]='a';s2[1]=NULL; ^~~~ main.cpp:34:15: warning: converting to non-pointer type 'char' from NULL [-Wconversion-null] s1[j]=NULL; ^~~~ main.cpp:37:35: warning: converting to non-pointer type 'char' from NULL [-Wconversion-null] s2[j-1]='a';s2[j]=NULL;jant=j; ^~~~