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#include <stdio.h>
#include <string.h>
/* The C Programming Language: 2nd Edition
*
* Exercise 4-13: Write a recursive version of the function reverse(s), which
* reverses the string `s` in place.
*
* Answer: Much like the last exercise, the trick is in terminating your flow
* early and resetting state for the next string.
*/
void reverse(char[]);
int main() {
char foo[40] = "Learning C is fun and challenging.";
printf("Before: %s\n", foo);
reverse(foo);
printf(" After: %s\n", foo);
/* I don't know how to set a char array to another string... */
char bar[30] = "Hello out there!";
printf("Before: %s\n", bar);
reverse(bar);
printf(" After: %s\n", bar);
return 0;
}
void reverse(char s[]) {
static int i = 0;
static int j = 0;
int c;
if (j == 0) {
j = strlen(s) - 1;
}
if (i < j) {
c = s[i];
s[i] = s[j];
s[j] = c;
i++;
j--;
reverse(s);
return;
}
i = 0;
j = 0;
}
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