/* 
 * 建立圖(自己輸入資料)
 */
public MatrixDG() {

    // 輸入"頂點數"和"邊數"
    System.out.printf("input vertex number: ");
    int vlen = readInt();
    System.out.printf("input edge number: ");
    int elen = readInt();
    if ( vlen < 1 || elen < 1 || (elen > (vlen*(vlen - 1)))) {
        System.out.printf("input error: invalid parameters!\n");
        return ;
    }

    // 初始化"頂點"
    mVexs = new char[vlen];
    for (int i = 0; i < mVexs.length; i++) {
        System.out.printf("vertex(%d): ", i);
        mVexs[i] = readChar();
    }

    // 初始化"邊"
    mMatrix = new int[vlen][vlen];
    for (int i = 0; i < elen; i++) {
        // 讀取邊的起始頂點和結束頂點
        System.out.printf("edge(%d):", i);
        char c1 = readChar();
        char c2 = readChar();
        int p1 = getPosition(c1);
        int p2 = getPosition(c2);

        if (p1==-1 || p2==-1) {
            System.out.printf("input error: invalid edge!\n");
            return ;
        }

        mMatrix[p1][p2] = 1;
    }
}