上三角蛇形矩阵

emmm……
 1 #include <iostream>
 2 using  namespace std;
 3 int a[100][100]={0};
 4 int main()
 5 {
 6     int n,x=0,y=0,t=1;
 7     cin>>n;
 8     int sum=(n*n+n)/2; //上三角的个数;
 9     a[x][y]=1;
10     while(t<(n*n+n)/2)
11     {
13         a[x][++y]=++t;
14         while(y-1>=0&&!a[x+1][y-1])
15             a[++x][--y]=++t;
16         a[++x][y]=++t;
17         while(x-1>=0&&!a[x-1][y+1])
18             a[--x][++y]=++t;
19     }
20     for(int i=0;i<n;i++)
21     {
22         cout<<endl;
23         for(int j=0;j<n;j++)
24             if(a[i][j])
25                 cout<<a[i][j]<<" ";
26             else
27                 cout<<" "<<" ";
28     }
29     cout<<endl;
30     return 0;
31 }