Can anyone help in explaining this C++ code?

Question

Hi All,

Can anyone help in explaining this type of code.

arrayData[2].Value = m_noAt = 0;

Answer 1

The value of array variable arryData[2].Value and m_noAt are both set to zero.

Answer 2

Explanation of :  arrayData[2].Value = m_noAt = 0

Assignment is done from right to left. Here assignment is done in two steps.

step 1: m_noAt is set to 0

step 2: the value of m_noAt is set to arrayData[2]

So finally, both arrayData[2] and m_noAt is set to 0

Hope u got the answer

Answer 3

In C and C++ an assignment is also an expression and therefore has a value. The "value" of m_noAt = 0 is 0. This allows you to combine multiple assignments like

arrayData[2].Value = m_noAt = 0;

This is equivalent to

arrayData[2].Value = (m_noAt = 0);

Which says assign 0 to m_noAt, then assign the result of (m_noAt = 0) which is 0 to arrayData[2].Value.

Another common way this feature is used is in code such as

while ((c = getchar()) != 'q')

{ // do stuff }

This assigns the result of getchar() to c and then uses the value of the assignment (also the result of getchar()) to compare with 'q'.

Also, I assume arrayData is an array of structures or classes. One member of the class/struct is Value.

Hope that helps,

Jon

Answer 4

Setting the value of arrayData[2] and m_noAt as Zero;

arrayData[2].Value----->Third value of the array;