Compilare: user.cpp: In function ‘void backtr(int, int, int, int)’: user.cpp:41:7: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(M[i-2][j]==0) ^ user.cpp:51:7: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(M[i+2][j]==0) ^ user.cpp:61:7: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(M[i][j-2]==0) ^ user.cpp:71:7: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(M[i][j+2]==0) ^