for (int i=0;i<4; i++) a[i] += 2;
for (int i=0;i<4; i++) a[i] *= 2;
for (int i= 1;i<= 4; i++) a[i]= a[i]* a[i];
for (int i= 1;i<= 4; i++) a[i] *= 2;