Compilare: main.cpp: In function 'int main()': main.cpp:20:23: warning: array subscript has type 'char' [-Wchar-subscripts] fr[b[i][j]]++; ^ main.cpp:30:77: warning: array subscript has type 'char' [-Wchar-subscripts] if ( d[i][j] - d[i-m][j] - d[i][j-m] + d[i-m][j-m] != fr[lit] ); ^ main.cpp:30:17: warning: this 'if' clause does not guard... [-Wmisleading-indentation] if ( d[i][j] - d[i-m][j] - d[i][j-m] + d[i-m][j-m] != fr[lit] ); ^~ main.cpp:31:21: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if' ok[i][j] = 1; ^~