/in/foo.c: In function 'main':
/in/foo.c:10:2: error: 'm' undeclared (first use in this function)
  m=a[0];
  ^
/in/foo.c:10:2: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:6:20: warning: unused variable 't' [-Wunused-variable]
  int n,k,i,j,x,y,z,t;
                    ^
/in/foo.c:6:18: warning: unused variable 'z' [-Wunused-variable]
  int n,k,i,j,x,y,z,t;
                  ^
/in/foo.c:6:16: warning: unused variable 'y' [-Wunused-variable]
  int n,k,i,j,x,y,z,t;
                ^
/in/foo.c:6:14: warning: unused variable 'x' [-Wunused-variable]
  int n,k,i,j,x,y,z,t;
              ^
/in/foo.c:6:12: warning: unused variable 'j' [-Wunused-variable]
  int n,k,i,j,x,y,z,t;
            ^