foo.c: In function 'main':
foo.c:5:27: error: expected expression before ')' token
    5 |         for(int b=0;b<n;++){
      |                           ^
foo.c:6:29: error: 'j' undeclared (first use in this function)
    6 |                 for(int j=0;j<b+1;j++){
      |                             ^
foo.c:6:29: note: each undeclared identifier is reported only once for each function it appears in

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