Answer to Question #59477 in C++ for Salem

Question

// a program lists all permutations of ABCDEF in which A appears before D

#include <cstring>
#include <iostream>
#include <cstdio>
#include <cstdlib>
using namespace std;

void swap(char *x, char *y)
{
char temp;
temp = *x;
*x = *y;
*y = temp;
}

void permute(char *a, int l, int r)
{
int i;
if (l == r)
cout << "A" << a << endl;
else
{
for (i = l; i <= r; i++)
{
swap((a+l), (a+i));
permute(a, l+1, r);
swap((a+l), (a+i));
}
}
}

int main()
{
char str[] = "BCDEF";
int n = strlen(str);
permute(str, 0, n-1);

return 0;
}

How can I make it work correct?