The first table is fine (as I have added it to page 2) and table 2 and 3, I want to add them at about page 5. Its the same code for them too but they are displaying at the end of document and with a gap. I have used [t] for the top of the page. I have shifted the code even at the start of the document, still showing up at the end. Works well for the 1st table not for the second.
Code:
\begin{table*}[t]
\centering
\caption{Directed Graph}
\begin{tabular}{|c|c|c|c|c|c|c|c|c|} \hline
Name&Nodes&Edges&k=1(time)&k=1($\%$ ratio)&k=10(time)&k=10($\%$ ratio)&k=100(time)&k=100($\%$ ratio)\\ \hline
Core-Citation& 23166& 91500&0.701 &0.0103 &1.035 &0.017 &2.300 &0.0327 \\ \hline
HEP-TH & 27710 & 352807 &4.355 &0.0231 &8.0834 &0.04655 &12.833&0.0747 \\ \hline
Slashdot& 82168& 948464&1.927 &0.0001 &9.586 &0.0071 &54.232 &0.0449 \\ \hline
Web-Stanford& 281903 &2312497 & 973.69& 0.065&1631.48 &0.106 &2013.64 &0.106 \\ \hline
Youtube Links&1138499 &4942297 &200.23 &0.0014 &583.22 &0.0050 &1034.674 & 0.00811\\
\hline\end{tabular}
\end{table*}
\begin{table*}
\centering
\caption{Un-Directed Graph}
\begin{tabular}{|c|c|c|c|c|c|c|c|c|} \hline
Name&Nodes&Edges&k=1(time)&k=1($\%$ ratio)&k=10(time)&k=10($\%$ ratio)&k=100(time)&k=100($\%$ ratio)\\ \hline
COND-MAT&23133 &93497 &0.6701 &0.0024 &1.541 &0.0109 &5.618 &0.0591 \\ \hline
Email-Enron&36692 &183831 &0.423 &0.0010 &0.743 &0.0028 &4.6102 &0.0238 \\ \hline
Brightkite&58228 &214078 &10.1704 &0.024 &10.145 &10.170 &13.202 &0.0291 \\ \hline
Amazon(MDS)&334863 &925872 &2.968 &0.0000831 &3.190 &0.0000855 &3.711 &0.0000978 \\ \hline
Hyves&1402673 &2777419 &3119.21 &0.0132 & 4229.20 & 0.0136& 4772.69 &0.01490 \\
\hline\end{tabular}
\end{table*}

[t]on your first table is to prevent the table being placed on a float page so makes it much more likely that both tables go to the end. – David Carlisle Dec 14 '16 at 19:50table*environments rather than the more commontableenvironments? Is it because you have a two-column document and want the tables to span both columns? – Mico Dec 14 '16 at 20:29