写了个交互库，结果提交代码时编译错误：

No valid executable file was produced by the compiler
/nix/store/js66s0xwjnzg0ggi2lq9bcvlk6x2za13-binutils-2.35.2/bin/ld: ./ccRNdjFr.o:(.bss+0x1f40): multiple definition of `ans'; /tmp/compiler_4pt9msnn/lib.o:(.bss+0xf46680): first defined here
/nix/store/js66s0xwjnzg0ggi2lq9bcvlk6x2za13-binutils-2.35.2/bin/ld: ./ccRNdjFr.o: in function `main':
src:(.text+0x0): multiple definition of `main'; /tmp/compiler_4pt9msnn/lib.o:src:(.text.startup+0x0): first defined here
collect2: 错误：ld 返回 1

这是什么问题？该怎么解决？ 求dalao解疑。