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recursion_basic.c
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recursion_basic.c
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#include <stdio.h>
#include <string.h>
/****************************************************************************
* A recursive function to print a string character-by-character. Uses pointer
* arithmetic. Is moderately fancy.
*****************************************************************************/
void print_string(char *str, int len)
{
if (len == 0)
{
printf("\n");
return;
}
printf("%c", str[0]);
print_string(str + 1, len - 1);
}
/****************************************************************************
* A recursive function to print a string character-by-character. Uses pointer
* arithmetic. Is very fancy.
****************************************************************************/
void print_string_a_little_bit_more_difficult(char *str)
{
// Recall that *str and str[0] are synonymous
if (*str == '\0')
{
printf("\n");
return;
}
printf("%c", *str);
print_string_a_little_bit_more_difficult(str + 1);
}
/****************************************************************************
* return the minimum of two integers
****************************************************************************/
int min(int a, int b)
{
// conditional operator is awesome
return (a < b) ? a : b;
}
/****************************************************************************
* This is how I would implement the recursive solution.
****************************************************************************/
int sz_array_min(int *array, int n)
{
// If there's just one element in our array, that's the minimum element in
// the array.
if (n == 1)
return array[0];
// Take the minimum of the last element in the array, or the minimum element
// among the first (n - 1) elements of the array.
return min(array[n - 1], sz_array_min(array, n - 1));
}
/**********************************************************
* This is just a different way of writing faster_power().
* returns a^b
********************************************************/
int faster_power_extra_fancy(int a, int b)
{
int x;
if (b == 0)
return 1;
x = faster_power_extra_fancy(a, b / 2);
x = x * x;
x = (b % 2) ? (x * a) : x;
return x;
}
/****************************
* returns the facorial of n
* this cant handle huge numbers
****************************/
long factorial(int n)
{
if (n == 0)
return 1;
else
return(n * factorial(n-1));
}
int main()
{
int a = 3, b = 7;
a = faster_power_extra_fancy(a,b);
printf("the output was %d \n",a);
}