Direct and Indirect Recursion
Table of Content:
Before starting this tutorial please read the previous tutorial first Concept of Recursion
Direct Recursion
When in the body of a method there is a call to the same method, we say that the method is directly recursive. That means Direct recursion occurs when a method invokes itself.
Indirect Recursion or mutually recursive
If method A calls method B, method B calls method C, and method C calls method A we call the methods A, B and C indirectly recursive or mutually recursive.
Indirect recursion occurs when a method invokes another method, eventually resulting in the original method being invoked again.
Chains of calls in indirect recursion can contain multiple methods, as well as branches, i.e. in the presence of one condition one method to be called, and provided a different condition another to be called.
The depth of indirection may vary.
Indirect recursion requires the same attention to base cases.
| Direct Recursion | Indirect Recursion |
| In the direct recursion, only one function is called by itself. | In indirect recursion more than one function are by the other function and number of times. |
| direct recursion makes overhead. | The indirect recursion does not make any overhead as direct recursion |
| The direct recursion called by the same function | While the indirect function called by the other function |
| In direct function, when function called next time, value of local variable will stored | but in indirect recursion, value will automatically lost when any other function is called local variable |
| Direct function engaged memory location | while local variable of indirect function not engaged it |
Structure of direct function
int num()
{
...
...
int num();
}
|
Structure of indirect function
int num()
{
...
...
int sum();
}
int sum()
{
...
...
int num();
}
|