Compilare: main.cpp: In function 'int main()': main.cpp:15:12: warning: array subscript has type 'char' [-Wchar-subscripts] f[x]++; ^ main.cpp:17:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation] for(int i=m;i<=n;i++) ^~~ main.cpp:20:9: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for' for(char ch='a';ch<='z';ch++){ ^~~ main.cpp:32:23: warning: array subscript has type 'char' [-Wchar-subscripts] if(t!=f[ch]) ^