/in/foo.c: In function 'main':
/in/foo.c:31:10: error: 'not' undeclared (first use in this function)
      if (not print[fat[i][j]]) 
          ^~~
/in/foo.c:31:10: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:31:14: error: expected ')' before 'print'
      if (not print[fat[i][j]]) 
              ^~~~~