/in/foo.c: In function 'main':
/in/foo.c:4:10: warning: format '%d' expects argument of type 'int *', but argument 2 has type 'int' [-Wformat=]
  scanf("%d",N);
          ^
/in/foo.c:8:16: warning: statement with no effect [-Wunused-value]
  for (i=0;i<n;i+1){
               ~^~
/in/foo.c:9:10: warning: format '%d' expects argument of type 'int *', but argument 2 has type 'int' [-Wformat=]
  scanf("%d",a[i]);
          ^
/in/foo.c:13:11: warning: format '%f' expects argument of type 'double', but argument 2 has type 'int' [-Wformat=]
  printf("%f",S);
           ^
/in/foo.c:11:9: warning: variable 'A' set but not used [-Wunused-but-set-variable]
  double A=0;
         ^
/in/foo.c:4:2: warning: 'N' is used uninitialized in this function [-Wuninitialized]
  scanf("%d",N);
  ^~~~~~~~~~~~~