Compilare: main.cpp: In function 'int pre(trie*, char*, int)': main.cpp:70:25: warning: left operand of comma operator has no effect [-Wunused-value] return ( x->nod[ ch ], s + 1, i + 1 ); ~~~~~~~~~~~^ main.cpp:70:30: warning: right operand of comma operator has no effect [-Wunused-value] return ( x->nod[ ch ], s + 1, i + 1 ); ~~^~~