Compilare: main.cpp: In function 'bool check()': main.cpp:27:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation] for(int i=1;i<=n;i++) ^~~ main.cpp:42:3: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for' return (a||b||c||d); ^~~~~~ main.cpp: At global scope: main.cpp:47:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type] main() ^ main.cpp: In function 'int main()': main.cpp:49:11: warning: 'j' may be used uninitialized in this function [-Wmaybe-uninitialized] int i,j,c; ^