Compilare: user.cpp:48:37: warning: multi-character character constant [-Wmultichar] for(int i=1;i<=n;i++) mat[i][0]='-1',mat[i][m+1]='-1'; ^ user.cpp:48:54: warning: multi-character character constant [-Wmultichar] for(int i=1;i<=n;i++) mat[i][0]='-1',mat[i][m+1]='-1'; ^ user.cpp:49:37: warning: multi-character character constant [-Wmultichar] for(int i=1;i<=m;i++) mat[0][i]='-1',mat[n+1][i]='-1'; ^ user.cpp:49:54: warning: multi-character character constant [-Wmultichar] for(int i=1;i<=m;i++) mat[0][i]='-1',mat[n+1][i]='-1'; ^ user.cpp: In function ‘int main()’: user.cpp:48:36: warning: overflow in implicit constant conversion [-Woverflow] for(int i=1;i<=n;i++) mat[i][0]='-1',mat[i][m+1]='-1'; ^ user.cpp:48:53: warning: overflow in implicit constant conversion [-Woverflow] for(int i=1;i<=n;i++) mat[i][0]='-1',mat[i][m+1]='-1'; ^ user.cpp:49:36: warning: overflow in implicit constant conversion [-Woverflow] for(int i=1;i<=m;i++) mat[0][i]='-1',mat[n+1][i]='-1'; ^ user.cpp:49:53: warning: overflow in implicit constant conversion [-Woverflow] for(int i=1;i<=m;i++) mat[0][i]='-1',mat[n+1][i]='-1'; ^