The format of a type definition is:
typedef <data type> <new data type>
So to define a new type Boolean:
typedef int Boolean;
Some sample C++ code using this:
const int FALSE = 0; // now use FALSE for 0
const int TRUE = 1; // now use TRUE for 1
typedef int Boolean; // new type (alias)
void main(void)
{
Boolean a, b, c; // declare 3 Booleans
a = TRUE; // set a to TRUE (1)
b = FALSE; // set b to FALSE (0)
c = a; // set c to a (1)
c = 1; // OK, Boolean is alias for int
// but it's not consistent
}