Language: C++

#include<iostream>
using namespace std;




int main()
{
&#160; int n;
&#160; int x1,x2,y1,y2,z1,z2,w1,w2;
&#160; int x,y,z,w;
&#160; while(cin>>n,n){
&#160; &#160; for(int i=0;i<n;i++){
&#160; &#160; &#160; cin>>x1>>y1>>z1>>w1>>x2>>y2>>z2>>w2;
&#160; &#160; &#160; x = x1*x2 - y1*y2 - z1*z2 - w1*w2;
&#160; &#160; &#160; y = x1*y2 + y1*x2 + z1*w2 - w1*z2;
&#160; &#160; &#160; z = x1*z2 - y1*w2 + z1*x2 + w1*y2;
&#160; &#160; &#160; w = x1*w2 + y1*z2 - z1*y2 + w1*x2;
&#160; &#160; &#160; printf("%d %d %d %d\n",x,y,z,w);
&#160; &#160; }
&#160; }
}

Compiler output:
a.cc:9:2: error: stray '#' in program
    9 | &#160; int n;
      |  ^
a.cc:10:2: error: stray '#' in program
   10 | &#160; int x1,x2,y1,y2,z1,z2,w1,w2;
      |  ^
a.cc:11:2: error: stray '#' in program
   11 | &#160; int x,y,z,w;
      |  ^
a.cc:12:2: error: stray '#' in program
   12 | &#160; while(cin>>n,n){
      |  ^
a.cc:13:2: error: stray '#' in program
   13 | &#160; &#160; for(int i=0;i<n;i++){
      |  ^
a.cc:13:9: error: stray '#' in program
   13 | &#160; &#160; for(int i=0;i<n;i++){
      |         ^
a.cc:14:2: error: stray '#' in program
   14 | &#160; &#160; &#160; cin>>x1>>y1>>z1>>w1>>x2>>y2>>z2>>w2;
      |  ^
a.cc:14:9: error: stray '#' in program
   14 | &#160; &#160; &#160; cin>>x1>>y1>>z1>>w1>>x2>>y2>>z2>>w2;
      |         ^
a.cc:14:16: error: stray '#' in program
   14 | &#160; &#160; &#160; cin>>x1>>y1>>z1>>w1>>x2>>y2>>z2>>w2;
      |                ^
a.cc:15:2: error: stray '#' in program
   15 | &#160; &#160; &#160; x = x1*x2 - y1*y2 - z1*z2 - w1*w2;
      |  ^
a.cc:15:9: error: stray '#' in program
   15 | &#160; &#160; &#160; x = x1*x2 - y1*y2 - z1*z2 - w1*w2;
      |         ^
a.cc:15:16: error: stray '#' in program
   15 | &#160; &#160; &#160; x = x1*x2 - y1*y2 - z1*z2 - w1*w2;
      |                ^
a.cc:16:2: error: stray '#' in program
   16 | &#160; &#160; &#160; y = x1*y2 + y1*x2 + z1*w2 - w1*z2;
      |  ^
a.cc:16:9: error: stray '#' in program
   16 | &#160; &#160; &#160; y = x1*y2 + y1*x2 + z1*w2 - w1*z2;
      |         ^
a.cc:16:16: error: stray '#' in program
   16 | &#160; &#160; &#160; y = x1*y2 + y1*x2 + z1*w2 - w1*z2;
      |                ^
a.cc:17:2: error: stray '#' in program
   17 | &#160; &#160; &#160; z = x1*z2 - y1*w2 + z1*x2 + w1*y2;
      |  ^
a.cc:17:9: error: stray '#' in program
   17 | &#160; &#160; &#160; z = x1*z2 - y1*w2 + z1*x2 + w1*y2;
      |         ^
a.cc:17:16: error: stray '#' in program
   17 | &#160; &#160; &#160; z = x1*z2 - y1*w2 + z1*x2 + w1*y2;
      |                ^
a.cc:18:2: error: stray '#' in program
   18 | &#160; &#160; &#160; w = x1*w2 + y1*z2 - z1*y2 + w1*x2;
      |  ^
a.cc:18:9: error: stray '#' in program
   18 | &#160; &#160; &#160; w = x1*w2 + y1*z2 - z1*y2 + w1*x2;
      |         ^
a.cc:18:16: error: stray '#' in program
   18 | &#160; &#160; &#160; w = x1*w2 + y1*z2 - z1*y2 + w1*x2;
      |                ^
a.cc:19:2: error: stray '#' in program
   19 | &#160; &#160; &#160; printf("%d %d %d %d\n",x,y,z,w);
      |  ^
a.cc:19:9: error: stray '#' in program
   19 | &#160; &#160; &#160; printf("%d %d %d %d\n",x,y,z,w);
      |         ^
a.cc:19:16: error: stray '#' in program
   19 | &#160; &#160; &#160; printf("%d %d %d %d\n",x,y,z,w);
      |                ^
a.cc:20:2: error: stray '#' in program
   20 | &#160; &#160; }
      |  ^
a.cc:20:9: error: stray '#' in program
   20 | &#160; &#160; }
      |         ^
a.cc:21:2: error: stray '#' in program
   21 | &#160; }
      |  ^
a.cc: In function 'int main()':
a.cc:9:3: error: lvalue required as unary '&' operand
    9 | &#160; int n;
      |   ^~~
a.cc:10:3: error: lvalue required as unary '&' operand
   10 | &#160; int x1,x2,y1,y2,z1,z2,w1,w2;
      |   ^~~
a.cc:11:3: error: lvalue required as unary '&' operand
   11 | &#160; int x,y,z,w;
      |   ^~~
a.cc:12:3: error: lvalue required as unary '&' operand
   12 | &#160; while(cin>>n,n){
      |   ^~~
a.cc:13:3: error: lvalue required as unary '&' operand
   13 | &#160; &#160; for(int i=0;i<n;i++){
      |   ^~~
a.cc:13:10: error: lvalue required as unary '&' operand
   13 | &#160; &#160; for(int i=0;i<n;i++){
      |          ^~~
a.cc:14:3: error: lvalue required as unary '&' operand
   14 | &#160; &#160; &#160; cin>>x1>>y1>>z1>>w1>>x2>>y2>>z2>>w2;
      |   ^~~
a.cc:14:10: error: lvalue required as unary '&' operand
   14 | &#160; &#160; &#160; cin>>x1>>y1>>z1>>w1>>x2>>y2>>z2>>w2;
      |          ^~~
a.cc:14:17: error: lvalue required as unary '&' operand
   14 | &#160; &#160; &#160; cin>>x1>>y1>>z1>>w1>>x2>>y2>>z2>>w2;
      |                 ^~~
a.cc:15:3: error: lvalue required as unary '&' operand
   15 | &#160; &#160; &#160; x = x1*x2 - y1*y2 - z1*z2 - w1*w2;
      |   ^~~
a.cc:15:10: error: lvalue required as unary '&' operand
   15 | &#160; &#160; &#160; x = x1*x2 - y1*y2 - z1*z2 - w1*w2;
      |          ^~~
a.cc:15:17: error: lvalue required as unary '&' operand
   15 | &#160; &#160; &#160; x = x1*x2 - y1*y2 - z1*z2 - w1*w2;
      |                 ^~~
a.cc:16:3: error: lvalue required as unary '&' operand
   16 | &#160; &#160; &#160; y = x1*y2 + y1*x2 + z1*w2 - w1*z2;
      |   ^~~
a.cc:16:10: error: lvalue required as unary '&' operand
   16 | &#160; &#160; &#160; y = x1*y2 + y1*x2 + z1*w2 - w1*z2;
      |          ^~~
a.cc:16:17: error: lvalue required as unary '&' operand
   16 | &#160; &#160; &#160; y = x1*y2 + y1*x2 + z1*w2 - w1*z2;
      |                 ^~~
a.cc:17:3: error: lvalue required as unary '&' operand
   17 | &#160; &#160; &#160; z = x1*z2 - y1*w2 + z1*x2 + w1*y2;
      |   ^~~
a.cc:17:10: error: lvalue required as unary '&' operand
   17 | &#160; &#160; &#160; z = x1*z2 - y1*w2 + z1*x2 + w1*y2;
      |          ^~~
a.cc:17:17: error: lvalue required as unary '&' operand
   17 | &#160; &#160; &#160; z = x1*z2 - y1*w2 + z1*x2 + w1*y2;
      |                 ^~~
a.cc:18:3: error: lvalue required as unary '&' operand
   18 | &#160; &#160; &#160; w = x1*w2 + y1*z2 - z1*y2 + w1*x2;
      |   ^~~
a.cc:18:10: error: lvalue required as unary '&' operand
   18 | &#160; &#160; &#160; w = x1*w2 + y1*z2 - z1*y2 + w1*x2;
      |          ^~~
a.cc:18:17: error: lvalue required as unary '&' operand
   18 | &#160; &#160; &#160; w = x1*w2 + y1*z2 - z1*y2 + w1*x2;
      |                 ^~~
a.cc:19:3: error: lvalue required as unary '&' operand
   19 | &#160; &#160; &#160; printf("%d %d %d %d\n",x,y,z,w);
      |   ^~~
a.cc:19:10: error: lvalue required as unary '&' operand
   19 | &#160; &#160; &#160; printf("%d %d %d %d\n",x,y,z,w);
      |          ^~~
a.cc:19:17: error: lvalue required as unary '&' operand
   19 | &#160; &#160; &#160; printf("%d %d %d %d\n",x,y,z,w);
      |                 ^~~
a.cc:20:3: error: lvalue required as unary '&' operand
   20 | &#160; &#160; }
      |   ^~~
a.cc:20:10: error: lvalue required as unary '&' operand
   20 | &#160; &#160; }
      |          ^~~
a.cc:21:3: error: lvalue required as unary '&' operand
   21 | &#160; }
      |   ^~~