Compilare: user.cpp: In function ‘void Roy_Floyd(int)’: user.cpp:13:58: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if(a[i][j]>=a[i][k]+a[k][j]||!a[i][j]&&i!=j) ~~~~~~~~^~~~~~ user.cpp: In function ‘int main()’: user.cpp:36:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&n); ^ user.cpp:38:59: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(j=1;j<=n;j++)fscanf(f,"%d",&a[i][j]),t[i][j]=1; ^