C ++：在switch语句中构建阵列 [英] C++: Construct arrays inside a switch statement

问题描述

我试图构建具有其中一个将被随机选择了几个不同配置的阵列。在code我第一次尝试是：

I'm trying to construct an array that has a few different configurations where one will be selected randomly. The code I tried first is:

void createArray() {
    int* tileVals;
    int randInt = rand() % 3;
    switch (randInt) {
    case 0:
            int tileVals[] = {1,1,1,2,2,2,3,3,3};
            break;
    case 1:
            int tileVals[] = {1,1,1,1,2,2,3,3,3};
            break;
    case 2:
            int tileVals[] = {1,1,1,1,2,2,2,3,3};
            break;
    }
    // Do stuff with tileVals
}

但我得到的编译器错误：

But I got the compiler error:

src/Board.cpp:67:7: error: redefinition of 'tileVals'
        int tileVals[] = {1,1,1,1,2,2,2,3,3};
src/Board.cpp:70:7: error: redefinition of 'tileVals'
        int tileVals[] = {1,1,1,2,2,2,2,3,3};
...

我明年受审：

void createArray() {
    int* tileVals;
    int randInt = rand() % 3;
    switch (randInt) {
    case 0:
            int case0[] = {1,1,1,2,2,2,3,3,3};
            tileVals = case0;
            break;
    case 1:
            int case1[] = {1,1,1,1,2,2,3,3,3};
            tileVals = case1;
            break;
    case 2:
            int case2[] = {1,1,1,1,2,2,2,3,3};
            tileVals = case2;
            break;
    }
    // Do stuff with tileVals
}

但是，这回来了一个编译器错误：

But this came back with a compiler error:

src/Board.cpp:85:2: error: switch case is in protected scope
    case 6:
         ^
src/Board.cpp:82:7: note: jump bypasses variable initialization
    int case5[] = {1,1,1,2,2,3,3,3,3};
...

我知道我可以通过具有每个案例语句然后分配值是switch语句之外创建的tileVals数组中环做，但是这似乎并不像一个非常有效的方式来做到这一点。有没有更好的办法？谢谢你。

I know I could do it by having a for loop inside each case statement that then assigned the values to a tileVals array that is created outside the switch statement, but that doesn't seem like a very efficient way to do this. Is there a better way? Thanks.

推荐答案

如果您不要修改 tileVals 在以后code的内容，你可以做它如下：

If you do not modify the content of tileVals in the later code, you could do it as follows:

void createArray() {
    int * tileVals;
    int randInt = rand() % 3;
    int cases[][9] = { {1, 1, 1, 2, 2, 2, 3, 3, 3},
                       {1, 1, 1, 1, 2, 2, 3, 3, 3},
                       {1, 1, 1, 1, 2, 2, 2, 3, 3} };
    tileVals = cases[randInt];
    // Do stuff with tileVals
}

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