如何将局部变量传递给另一个函数？

Question

所以我在做一个文字冒险游戏。它有数百条故事线，一个功能齐全的战斗系统，我现在正在尝试创建一个影响系统。基本上它应该是这样工作的：某些反应/动作会增加或减少你对不同角色的影响。我想在choice_6() 和story_7() 中使用影响变量。我怎么做？请不要给我任何链接。我已经经历了许多其他答案，但它们对我来说没有意义，所以如果您要复制和粘贴，至少要以与其他答案不同的方式解释它。谢谢。

int choice_6()
    {
        int influence = 0;
        int choice = 0;
        printf("What do you do?\n");
        printf("\t1. You: No. I know absolutely nothing about you. You could be a monster\n");
        printf("\ttoo for all I know! Normal people don't turn into frogs!\n");
        printf("\t2. You: Your right we should keep moving. You can tell me when your\n");
        printf("\tready.\n");
        printf("\t3. You: Okay where do you think should we go then?\n");
        do 
        {
            scanf_s("%i", &choice);
            switch (choice)
            {
                case 1:
                    {
                        printf("\tBrie flashes a pained look on her face and you immediately regret saying that.\n");
                        printf("\tBrie: You really think I'm a monster?\n");
                        system("pause");
                        influence -= 10;
                        printf("You lose influence and are now at %i with Brie.\n", influence);
                        system("pause");
                        printf("Influence affects characters reactions towards you, their combat effectiveness, and even their allegiances in rare cases.\n");
                        printf("However, depending on the situation, low influence is not always a bad thing...\n");
                        system("pause");
                        printf("\tYou: Your right we should keep moving.\n");
                        break;
                    }
                case 2:
                    {
                        printf("\tBrie: Thank you. I'd rather not discuss this my life story in a dark\n");
                        printf("\tdungeon.\n");
                        system("pause");
                        influence += 10;
                        printf("You gain influence and are now at %i influence with Brie.\n", influence);
                        system("pause");
                        printf("Influence affects characters reactions towards you, their combat effectiveness, and even their allegiances in rare cases.\n");
                        printf("However, depending on the situation, low influence is not always a bad thing...\n");
                        system("pause");
                        printf("\tYou: I'd have to agree with you there. Let's see what is up these stairs.\n");
                        choice = 2;
                        break;
                    }
                case 3:
                    {
                        printf("Brie smiles at this.\n");
                        printf("\tBrie: Well the only way out seems to be these stairs so let's go up.\n");
                        system("pause");
                        influence += 10;
                        printf("You gain influence and are now at %i influence with Brie.\n", influence);
                        system("pause");
                        printf("Influence affects characters reactions towards you, their effectiveness in combat, and even their allegiances in rare cases.\n");
                        printf("However, depending on the situation, low influence is not always a bad thing...\n");
                        system("pause");
                        printf("\tYou: Sounds good to me I am quite frankly done with dungeons about now.\n");
                        break;
                    }
                default:
                    {
                        printf("Type the number for the choice you want to do\n");
                        system("pause");
                        break;
                    }
            }
        }while(choice != 1 && choice != 2 && choice != 3);
    }

    int story_7()
    {
        printf("\ninfluence is %i\n", influence);
        printf("You lead the way walking upstairs\n");
        system("pause");
        printf("You turn the corner while crouched to find a room full of gremlins and goblins.\n");
        system("pause");
        printf("You grab Brie's hand and roll to the left behind some crates before they see you.\n");
        system("pause");
        printf("Even though you realize you will probably not make it out of this situation\n");
        printf("alive, you can't help but feel lucky with Brie being so tightly pressed against you on the floor.\n");
        system("pause");
        printf("After a long period of silence to confirm nobody has seen you both enter,\n");
        printf("Brie looks up at you and rolls her eyes.\n");
        system("pause");
        printf("*whispers*\tBrie: At least buy me dinner first jeez.\n");
        system("pause");
        printf("*whispers*\tYou: I'd love to but we should probably kill these uglies first.\n");
        system("pause");
        if (influence > 0)
        {
            printf("Brie laughs at this and slowly leans you off her to have both of you crouch.");
            system("pause");
        }
        else
        {
            printf("Brie: Ugh just get off of me!\n");
            printf("Brie pushes you off her violently and you manage to stay crouched.");
            system("pause");
        }
    }



    int main()
{
    int play = 0;
    int influence = 0;
    intro_1();
    story_1();
    choice_1();
    story_2();
    choice_2();
    story_3();
    choice_3();
    story_4();
    choice_4();
    story_5();
    choice_5();
    intro_2();
    combat_1();
    story_6();
    choice_6();
    story_7();
    choice_7();
    system("pause");
}

Answer 1

如果您想从函数中修改它，可以将 指针 传递给 influence 变量。像这样：

int choice_6(int *influence)
{
    // ...
    *influence -= 10;
    // use *influence wherever you would have had used influence before
    // ...
}

int story_7(int influence)
{
    // ...
    if (influence > 0) ...
    // ...
}

int main()
{
    int influence = 0;
    // ...
    choice_6(&influence);
    story_7(influence);
    // ...
}

这是将 指针 传递给 choice_6()，因为您需要在该函数中修改 influence。这会将 值 传递给 story_7()，因为您不需要在那里修改 influence 值。

Answer 2

您应该创建存储游戏状态的游戏对象，在这种情况下，是影响力和其他事件标志。

然后您需要将此游戏对象设置为全局对象，或者通过指针/引用将其传递给可能需要检查或修改游戏状态的每个函数。

struct MyGame {
    int influence;
    int has_cheese;
};

void choice_6(struct MyGame * game) {
    ...
    game->influence += 10;
    ...
}
int main(...) {
    struct MyGame game;
    game->influence = 0;
    game->has_cheese = FALSE; // or 0
    ...
    choice_6(&game);
    ....
}

Answer 3

您需要通过引用传递influence 变量。这意味着您提供引用的函数可以更改变量本身的值（而不仅仅是变量的副本）。

通过在函数签名中在参数前面加上 * 并在前面加上 & 进行传递：

int choice_6(int *influence)
    {
....

    int main()
{
    int play = 0;
    int influence = 0;
    choice_6(&influence);
....