Why does this print 1,1,2,3,4,5 instead of 1,2,3,4,5?
#include <stdio.h>
#include <stdlib.h>
void print(int a[5], int n)
{
if(n > 0) {
print(a, --n);
}
printf(" %d", a[n]);
}
int main()
{
int n, a[] = {1,2,3,4,5};
n = sizeof(a) / sizeof(a[0]);
print(a, n);
return 0;
}
And how would you code it to print 1,2,3,4,5 using recursion in that manner ie traversing from the last?
The problem with your code is that you decrement n after the comparison in the if condition n > 0.
When print(a, 1) is called, the comparison n > 0 is true. Then n is decremented and, the recursive call is done and print(a, 0) evaluated. That fails the comparison and prints a[0] once. Then back in the calling function, a[0] is printed another time, since the local n after decrementing is also equal 0.
One way to fix it is to decrement n before doing the comparison with zero.
n-1as your second parameter in your recursion, rather than changing it via pre-decrement. And note, you'll have to change something else too (left as exercise).