8皇后源码，回溯

#include <stdio.h>
#include <math.h>
#define n 8
#define false 0
#define true 1

int x[n];
int place(int k)
{
int i=1;
while(i<k)
{
if((x[i]==x[k])||(abs(x[i]-x[k])==abs(i-k)))
return false;
i++;
}
return true;
}
void main(){
int i,k; 
int sum=0;
int place(int k);
x[1] = 0;k = 1;
while(k>0)
{
    x[k] = x[k]+1;
while((x[k]<=n) && (!place(k))==1)
{
x[k]=x[k]+1;
}