java类型不可见错误？怎么解决？

我使用的是eclipse,代码如下：
//Tdcppgraph.java
package tGraph;
import java.io.*;
class TEdge
{//图的边的数据结构
public TEdge()
...
public TEdge(TEdge e)
...
public int getCost(int t)
...
public int costs[];
int interLen[];
public int eN = 0;
int timeLim;
}
class TVertex
{//表示图节点的数据结构
public TVertex()
...
public TVertex(TVertex v)
...
public int k;
public int ad[];
//other info for later
}
public class TdcppGraph
{//表示时间依赖无向图的数据结构
public TdcppGraph()
...
public TdcppGraph(TdcppGraph g)
...

public TEdge Edge(int i,int j)
...
public void getGraphData(String name)
...
public void printInfo()
...