Compilare: main.cpp: In function 'void euler(int)': main.cpp:14:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<a[x].size(); i++) ~^~~~~~~~~~~~ main.cpp:20:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation] if(y==x) ^~ main.cpp:22:13: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if' euler(y); ^~~~~