Lỗi "multiple definition of mainCRTStartup" khi compile code trên codeblocks

[Paladiner]

Xin chào em là người mới ạ. Mn cho em hỏi là nó bị lỗi như dưới thì em sửa kiểu gì ạ ?

||=== Build file: "no target" in "no project" (compiler: unknown) ===|
C:\Users\Tien Vinh\Desktop\bai tap codeblock\Untitled1.o:crt1.c|| multiple definition of `mainCRTStartup'|
C:\Program Files\CodeBlocks\MinGW\bin\..\lib\gcc\mingw32\5.1.0\..\..\..\crt2.o:crt1.c|| first defined here|
C:\Users\Tien Vinh\Desktop\bai tap codeblock\Untitled1.o:crt1.c|| multiple definition of `WinMainCRTStartup'|
C:\Program Files\CodeBlocks\MinGW\bin\..\lib\gcc\mingw32\5.1.0\..\..\..\crt2.o:crt1.c|| first defined here|
C:\Users\Tien Vinh\Desktop\bai tap codeblock\Untitled1.o:crt1.c|| multiple definition of `atexit'|
C:\Program Files\CodeBlocks\MinGW\bin\..\lib\gcc\mingw32\5.1.0\..\..\..\crt2.o:crt1.c|| first defined here|
C:\Users\Tien Vinh\Desktop\bai tap codeblock\Untitled1.o:crt1.c|| multiple definition of `_onexit'|
C:\Program Files\CodeBlocks\MinGW\bin\..\lib\gcc\mingw32\5.1.0\..\..\..\crt2.o:crt1.c|| first defined here|
C:\Users\Tien Vinh\Desktop\bai tap codeblock\Untitled1.o:cygming-crtbegin.c|| multiple definition of `__gcc_register_frame'|
C:\Program Files\CodeBlocks\MinGW\bin\..\lib\gcc\mingw32\5.1.0\crtbegin.o:cygming-crtbegin.c|| first defined here|
C:\Users\Tien Vinh\Desktop\bai tap codeblock\Untitled1.o:cygming-crtbegin.c|| multiple definition of `__gcc_deregister_frame'|
C:\Program Files\CodeBlocks\MinGW\bin\..\lib\gcc\mingw32\5.1.0\crtbegin.o:cygming-crtbegin.c|| first defined here|
||error: ld returned 1 exit status|
||=== Build failed: 13 error(s), 0 warning(s) (0 minute(s), 0 second(s)) ===|