What is the main variable?

Answer 1

Variables are names for which the value may be altered. That is, the value of a name is variable. For example:

int x; // Declares a variable named x.

int y = 0; // Declares and initialises a variable named y.

x = 5; // Changes the value of the variable named x.

y = x; // Changes the value of the variable named y.

By contrast, constants are names for which the value does not change:

const int z = 10; // Declares a constant named z, which will always have the value 10.

Answer 2

the main variable was the methodological quality of published research reports