C / C ++中的静态变量和指向静态变量的指针

问题描述

如果我有静态变量：

    #mainmenu loop
def main():
optcmd = 0
print("\n\nwelcome to the store. what do you wanna do?"
    "\n here are all the commands. enter a number to output. enjoy!"
    "\n 1: view your shopping list"
    "\n 2: add to the shopping list"
    "\n 3: delete items from the shopping list"
    "\n 4: clear the shopping list"
    "\n 5: go to isle 1"
    "\n 6: go to isle 2"
    "\n 7: go to isle 3"
    "\n 8: go to isle 4"
    "\n 9: checkout"
    "\n 10: leave the store")
while not optcmd:
    optcmd = int(input('>> '))
    if optcmd<=0 or optcmd>10:
    print('invalid code...\nPlease re-enter code...')
    optcmd=0
return optcmd

#functions for each command
#view list
def viewList(shoplist):
if shoplist==[]:
    print('the list is empty.')
else:
    print(shoplist)

#add
def addList(shoplist):
item = input("what would you like to add? ")
shoplist.append(item)
print(item,' has been added.')

#delete
def removeList(shoplist):
item = input("what would you like to remove? ")
shoplist.remove(item)
print(item,' has been deleted.')

#shopping list
shoplist = []
selected = main()
#selection item 
while selected:
#if/else statements for selection
if selected == 1:
    viewList(shoplist)
    selected = main()
elif selected == 2:
    addList(shoplist)
    selected = main()
elif selected == 3:
    removeList(shoplist)
    selected = main()
elif selected == 4:
    pass
    selected=''
elif selected == 5:
    pass
    selected=''
elif selected == 6:
    pass
    selected=''
elif selected == 7:
    pass
    selected=''
elif selected == 8:
    pass
    selected=''
elif selected == 9:
    pass
    selected=''
elif selected == 10:
    print('thanks for visiting :)')
    selected=''

如果指针看起来像这样，我希望有一个指针指向该变量：

static int a;

如果我将此f返回到带有静态类型为int *类型的指针的赋值语句的函数调用中，那么该变量可以在该函数中访问吗？

也：

static int* f;
f=&a;

解决方法

int a;
static int* f;
f=&a; // does this mean now a is a static variable and it will be retained until the program ends?

“ [D]这意味着现在a是一个静态变量吗？”

不，不是。 static属性仅适用于您明确定义为static的变量。在上面的示例中，只有f是static。 a的生命周期将在其周围范围结束时结束，从而使指向该点的任何指针在该时间点都是无效的。

static int b;
int* c;
c=&n; // is this possible? 

“ [这可能吗？”

是的，很好。局部静态变量的生命周期是程序的整个生命周期。全局变量（静态或非静态）也具有完整程序的生命周期。这意味着指向它们的指针将始终保持有效。

This storage-class specifier reference可能有助于通读。