/in/foo.c: In function 'main':
/in/foo.c:5:12: error: 'inty1' undeclared (first use in this function)
  int x1,x2;inty1,y2,y3;
            ^~~~~
/in/foo.c:5:12: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:5:18: error: 'y2' undeclared (first use in this function)
  int x1,x2;inty1,y2,y3;
                  ^~
/in/foo.c:5:17: warning: left-hand operand of comma expression has no effect [-Wunused-value]
  int x1,x2;inty1,y2,y3;
                 ^
/in/foo.c:5:21: error: 'y3' undeclared (first use in this function)
  int x1,x2;inty1,y2,y3;
                     ^~
/in/foo.c:5:20: warning: left-hand operand of comma expression has no effect [-Wunused-value]
  int x1,x2;inty1,y2,y3;
                    ^
/in/foo.c:8:2: error: 'y1' undeclared (first use in this function)
  y1=x1+x2;
  ^~