大神们给解释一下，为啥第三个输出z=10，m()函数中的z可以传回主函数中吗
#include <stdio.h>int z=5;
m( )
{ static int x=2; int y=5; x=x+2; z=z+5; y=y+z;
printf ("%3d%3d\n", x, z); }
main( )
{ static int x=10; int y; y=z;
printf ("%3d%3d\n", x, z); m( );
printf ("%3d%3d\n", x, z); m( ); }
