Compilare: user.cpp: In function ‘void qsort(int, int)’: user.cpp:22:49: warning: operation on ‘x[j]’ may be undefined [-Wsequence-point] x[i] = x[i] + x[j] - ( x[j] = x[i] ); ^ user.cpp:23:49: warning: operation on ‘y[j]’ may be undefined [-Wsequence-point] y[i] = y[i] + y[j] - ( y[j] = y[i] ); ^ user.cpp:24:59: warning: operation on ‘ind[j]’ may be undefined [-Wsequence-point] ind[i] = ind[i] + ind[j] - ( ind[j] = ind[i] ); ^