C recursive
Recursion refers to the definition of the function method used in the function itself.
for example:
There was once a mountain, the mountain there was a temple, the temple has an old monk, was telling stories to young monk it! What story is it? "There was once a mountain, the mountain there was a temple, the temple has an old monk, was telling stories to young monk it! What story is it? 'There was once a mountain, the mountain there was a temple, the temple has an old monk, is a story to the young monk it! What story is it? ...... ''
Syntax is as follows:
void recursion()
{
recursion(); /* 函数调用自身 */
}
int main()
{
recursion();
}
C language support recursion, that is, a function can call itself. However, when using recursion, the programmer should be noted that the definition of a function exits from the conditions, otherwise it will go into an infinite loop.
Recursive function in solving many mathematical problems played a crucial role, such as the calculation of the factorial of a number, generate Fibonacci number, and so on.
Number factorial
The following example uses a recursive function to calculate the factorial of a given number:
#include <stdio.h>
double factorial(unsigned int i)
{
if(i <= 1)
{
return 1;
}
return i * factorial(i - 1);
}
int main()
{
int i = 15;
printf("%d 的阶乘为 %f\n", i, factorial(i));
return 0;
}
When the above code is compiled and executed, it produces the following results:
15 的阶乘为 1307674368000.000000
Fibonacci number
Fibonacci The following example uses a recursive function to generate a given number of columns:
#include <stdio.h>
int fibonaci(int i)
{
if(i == 0)
{
return 0;
}
if(i == 1)
{
return 1;
}
return fibonaci(i-1) + fibonaci(i-2);
}
int main()
{
int i;
for (i = 0; i < 10; i++)
{
printf("%d\t%n", fibonaci(i));
}
return 0;
}
When the above code is compiled and executed, it produces the following results:
0 1 1 2 3 5 8 13 21 34