---警告如下:a2.c:6:5: warning: implicit declaration of function ‘gets’ [-Wimplicit-function-declaration] gets(a); ^ /tmp/cceyMQ7u.o: In function `main': a2.c:(.text+0x41): warning: the `gets' function is dangerous and should not be used. ---原因:问题出在程序中使用了 gets...