Compilare: user.cpp: In function ‘void roy_floyd(int, int (*)[100])’: user.cpp:12:38: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if(i!=j&&a[i][k]&&a[k][j]&&(a[i][j]>a[i][k]+a[k][j])||!a[i][j]&&i!=j) a[i][j]=a[i][k]+a[k][j];} ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:18:9: warning: unused variable ‘i’ [-Wunused-variable] int i,j,n,a[100][100]; ^ user.cpp:18:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,n,a[100][100]; ^