Compilare: main.cpp:30:12: warning: multi-character character constant [-Wmultichar] g<<'-1'; ^~~~ main.cpp: In function 'int main()': main.cpp:26:13: warning: this 'if' clause does not guard... [-Wmisleading-indentation] if (a[i]==c) ^~ main.cpp:28:17: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if' g<<c<<" "<<na<<'\n'; ^