Main.c: In function 'main':
Main.c:5:21: error: 'n' undeclared (first use in this function)
    5 |         scanf("%d",&n);
      |                     ^
Main.c:5:21: note: each undeclared identifier is reported only once for each function it appears in
Main.c:8:17: error: 'flag' undeclared (first use in this function)
    8 |                 flag=0;
      |                 ^~~~
Main.c:3:13: warning: unused variable 'n\U0000ff0cflag' [-Wunused-variable]
    3 |     int i,j,n，flag=1;
      |             ^~~~~~~