foo.c: In function 'main':
foo.c:7:15: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
    7 |         while(a=1)
      |               ^
foo.c:10:5: warning: statement with no effect [-Wunused-value]
   10 |   {a%2;}
      |    ~^~
foo.c:12:13: warning: statement with no effect [-Wunused-value]
   12 |         {3*a+1;}
      |          ~~~^~

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