/in/foo.c: In function 'value':
/in/foo.c:20:14: error: expected declaration specifiers or '...' before numeric constant
  int x,apple(0);
              ^
/in/foo.c:23:3: error: 'apple' undeclared (first use in this function)
   apple+=A[i][x]*B[x][j];
   ^~~~~
/in/foo.c:23:3: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:26:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^