V707. Giving short names to global variables is considered to be bad practice.

The analyzer has detected a globally declared variable with a short name. Even if it won't cause any errors, it indicates a bad programming practice and makes the program text less comprehensible.

An example:

int i;

The problem about short variable names is that there is a large risk you'll make a mistake and use a global variable instead of a local one inside a function's or class method's body. For instance, instead of:

void MyFunc()
{
  for (i = 0; i < N; i++)
    AnotherFunc();
  ....
}

the following must be written:

void MyFunc()
{
  for (int i = 0; i < N; i++)
    AnotherFunc();
  ....
}

In cases like this, the analyzer will suggest changing the variable name to a longer one. The smallest length to satisfy the analyzer is three characters. It also won't generate the warning for variables with the names PI, SI, CR, LF.

The analyzer doesn't generate the warning for variables with short names if they represent structures. Although it's a bad programming practice as well, accidentally using a structure in an incorrect way is less likely. For example, if the programmer by mistake writes the following code:

struct T { int a, b; } i;
void MyFunc()
{
  for (i = 0; i < N; i++)
    AnotherFunc();
  ....
}

it simply won't compile.

However, the analyzer does get angry about constants with short names. They cannot be changed, but nothing prevents one from using them in an incorrect check. For example:

const float E = 2.71828;
void Foo()
{
  S *e = X[i];
  if (E)
  {
   e->Foo();
  }
  ....
}

The fixed code:

const float E = 2.71828;
void Foo()
{
  S *e = X[i];
  if (e)
  {
   e->Foo();
  }
  ....
}

But an even better way is to use a longer name or wrap such constants in a special namespace:

namespace Const
{
  const float E = 2.71828;
}