error in C "clang: error: linker command failed with exit code 1 (use -v to see invocation)"

Question

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I'm beginning C. I tried to print "helloworld" but it has error

I used visual studio code(Mac). installed C/C++,Code runner

I just follow the C lecture, but occurred error.

anyone know solution this error?

error message = ld: Undefined symbols: _main, referenced from: clang: error: linker command failed with exit code 1 (use -v to see invocation)