Compilare: user.cpp: In function ‘int valid(char)’: user.cpp:8:11: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if(x>='a' && x<='z' || x>='A' && x<='Z') ^ user.cpp: In function ‘int main()’: user.cpp:27:19: warning: unknown escape sequence: '\|' [enabled by default] if(strchr(". /\|-1234567890!><,'`~!@#$%^&*\"()_-+=;:",s[i])!=0 && valid(a)==1) ^