在循环中初始化变量

Question

我试图找出初始化某些变量时的最佳做法...我的代码目前看起来像这样:

int nHexCount = 0;
int prevState = sc.state;

bool bOnlySpaces = true;
bool bIsValidLabel = true;
bool bIsHotstring = false;
bool bIsValidName = true;
bool bIsValidExpStart = false;                         

bool fInExpression = false;
bool fInStringBlock = (sc.state == SCE_AHKL_STRINGOPTS || sc.state == SCE_AHKL_STRINGBLOCK);

for (; sc.More(); sc.Forward()) {

    if (sc.atLineStart) {
        if (!fInStringBlock && sc.state != SCE_AHKL_COMMENTBLOCK)
            sc.SetState(SCE_AHKL_DEFAULT);

        // Reset Status
        prevState = sc.state;

        bOnlySpaces = true;
        bIsValidLabel = true;
        bIsHotstring = false;
        bIsValidName = true;
        bIsValidExpStart = false;

        fInExpression = false;
    }

...

因此,每当我的程序在我正在编辑的编辑组件中找到一个新行时,您可以看到大多数这些变量都被重置...

问题是:

是否更好的编程实践声明并初始化for循环中的所有变量,或者我应该像现在这样离开它？

Answer 1

您应该尽可能地减少变量的范围.这将提高代码的可维护性,并减少错误的可能性.

// bad
int i, j, k;
k = 0;
for (i = 0; i < X, ++i)
{
  j = foo(i);
  k += j;
} 

bar(k);

......对......

// better
int k=0; // needs scope outside loop
for (int i = 0; i < X, ++i)
{
  int j = foo(i);
  k += j;
} 

bar(k);