/in/foo.cc: In function 'void init()':
/in/foo.cc:21:29: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
         while(scanf("%d",&x)==1&x)
               ~~~~~~~~~~~~~~^~~
/usr/lib/gcc/x86_64-linux-gnu/6/../../../x86_64-linux-gnu/Scrt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
collect2: error: ld returned 1 exit status