浅学作用域

#include <stdio.h>
int g_val=2021;//int为全局变量
int main()
{
printf("1:%d\n",g_val);
printf("hehe\n");


{int a=10;//int为局部变量
printf("a=%d\n",a);
printf("2:%d\n",g_val);
}


printf("3:%d\n",g_val);
system ("pause");
}