foo.c: In function 'main':
foo.c:6:17: warning: format '%d' expects argument of type 'int *', but argument 2 has type 'int' [-Wformat=]
    6 |         scanf("%d",x);
      |                ~^  ~
      |                 |  |
      |                 |  int
      |                 int *
foo.c:7:16: warning: right-hand operand of comma expression has no effect [-Wunused-value]
    7 |         for(i=0,i<=19,i++)
      |                ^
foo.c:7:26: error: expected ';' before ')' token
    7 |         for(i=0,i<=19,i++)
      |                          ^
      |                          ;
foo.c:7:26: error: expected expression before ')' token
foo.c:9:20: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
    9 |                 if(x=0)
      |                    ^
foo.c:17:32: error: invalid type argument of unary '*' (have 'int')
   17 |                         k=k+(2**i)*j;
      |                                ^~

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