Change my code, so that it doesn$$t bring any error when I compile it with g$++$ compiler. Also, I want my code to be in a C programming language format as much as possible. Here is my code about link state:

#include

#include

#include

#define MAX$\_$NODES $100$

#define INFINITY $999999$

int num$\_$nodes;

int graph$[$MAX$\_$NODES$][$MAX$\_$NODES$]$;

int dist$[$MAX$\_$NODES$]$;

int prev$[$MAX$\_$NODES$]$;

int visited$[$MAX$\_$NODES$]$;

void read$\_$topology$($const char $*$filename$)\{$

FILE $*$file $=$ fopen$($filename$,"$r$")$;

if $(!$file$)\{$

printf$("$Error: open input file.

$")$;

exit$(1)$;

$\}$

fscanf$($file$,"\%$d$",$ &num$\_$nodes$)$;

for $($int i $=0$; i $<$ num$\_$nodes; i$++)\{$

for $($int j $=0$; j $<$ num$\_$nodes; j$++)\{$

if $($i $==$ j$)\{$

graph$[$i$][$j$]=0$;

$\}$ else $\{$

graph$[$i$][$j$]=$ INFINITY;

$\}$

$\}$

$\}$

int node$1,$ node$2,$ cost;

while $($fscanf$($file$,"\%$d $\%$d $\%$d$",$ &node$1,$ &node$2,$ &cost$)!=$ EOF$)\{$

graph$[$node$1][$node$2]=$ cost;

graph$[$node$2][$node$1]=$ cost;

$\}$

fclose$($file$)$;

$\}$

void dijkstra$($int src$)\{$

for $($int i $=0$; i $<$ num$\_$nodes; i$++)\{$

dist$[$i$]=$ INFINITY;

prev$[$i$]=-1$;

visited$[$i$]=0$;

$\}$

dist$[$src$]=0$;

for $($int i $=0$; i $<$ num$\_$nodes; i$++)\{$

int min$\_$dist $=$ INFINITY;

int u $=-1$;

for $($int j $=0$; j $<$ num$\_$nodes; j$++)\{$

if $(!$visited$[$j$]$ && dist$[$j$]<$ min$\_$dist$)\{$

min$\_$dist $=$ dist$[$j$]$;

u $=$ j;

$\}$

$\}$

if $($u $==-1)$ break;

visited$[$u$]=1$;

for $($int v $=0$; v $<$ num$\_$nodes; v$++)\{$

if $(!$visited$[$v$]$ && graph$[$u$][$v$]!=$ INFINITY$)\{$

int new$\_$dist $=$ dist$[$u$]+$ graph$[$u$][$v$]$;

if $($new$\_$dist $<$ dist$[$v$])\{$

dist$[$v$]=$ new$\_$dist;

prev$[$v$]=$ u;

$\}$

$\}$

$\}$

$\}$

$\}$

void print$\_$routing$\_$table$($FILE $*$output$,$ int src$)\{$

for $($int i $=0$; i $<$ num$\_$nodes; i$++)\{$

fprintf$($output$,"\%$d $\%$d $\%$d

$",$ i$,$ prev$[$i$],$ dist$[$i$])$;

$\}$

fprintf$($output$,"$

$")$;

$\}$

void read$\_$messages$($const char $*$filename$,$ FILE $*$output$)\{$

FILE $*$file $=$ fopen$($filename$,"$r$")$;

if $(!$file$)\{$

printf$("$Error: open input file.

$")$;

exit$(1)$;

$\}$

int src$,$ dst;

char message$[1000]$;

while $($fscanf$($file$,"\%$d $\%$d$",$ &src$,$ &dst$)!=$ EOF$)\{$

fgets$($message$,$ sizeof$($message$),$ file$)$;

message$[$strlen$($message$)-1]=\text{'}\backslash 0\text{'}$; $//$ Remove newline character

dijkstra$($src$)$;

if $($dist$[$dst$]==$ INFINITY$)\{$

fprintf$($output$,$ "from $\%$d to $\%$d cost infinite hops unreachable message $\%$s

$",$ src$,$ dst$,$ message$)$;

$\}$ else $\{$

fprintf$($output$,$ "from $\%$d to $\%$d cost $\%$d hops", src$,$ dst$,$ dist$[$dst$])$;

int hop $=$ dst;

while $($prev$[$hop$]!=-1)\{$

fprintf$($output$,"\%$d$",$ hop$)$;

hop $=$ prev$[$hop$]$;

$\}$

fprintf$($output$,"$ message $\%$s

$",$ message$)$;

$\}$

$\}$

fclose$($file$)$;

$\}$

void apply$\_$changes$($const char $*$filename$)\{$

FILE $*$file $=$ fopen$($filename$,"$r$")$;

if $(!$file$)\{$

printf$("$Error: open input file.

$")$;

exit$(1)$;

$\}$

int node$1,$ node$2,$ cost;

while $($fscanf$($file$,"\%$d $\%$d $\%$d$",$ &node$1,$ &node$2,$ &cost$)!=$ EOF$)\{$

if $($cost $==-999)\{$

graph$[$node$1][$node$2]=$ INFINITY;

graph$[$node$2][$node$1]=$ INFINITY;

$\}$ else $\{$

graph$[$node$1][$node$2]=$ cost;

graph$[$node$2][$node$1]=$ cost;

$\}$

$\}$

fclose$($file$)$;

$\}$

int main$($int argc, char $*$argv$[])\{$

if $($argc $!=4)\{$

printf$("$usage: linkstate topologyfile messagesfile changesfile

$")$;

return $1$;

$\}$

read$\_$topology$($argv$[1])$;

FILE $*$output $=$ fopen$("$output$\_$ls$.$txt$","$w$")$;

if $(!$output$)\{$

printf$("$Error: open output file.

$")$;

return $1$;

$\}$

for $($int i $=0$; i $<$ num$\_$nodes; i$++)\{$

dijkstra$($i$)$;

print$\_$routing$\_$table$($output$,$ i$)$;

$\}$

read$\_$messages$($argv$[2],$ output$)$;

apply$\_$changes$($argv$[3])$;

for $($int i $=0$; i $<$ num$\_$nodes; i$++)\{$

dijkstra$($i$)$;

print$\_$routing$\_$table$($output$,$ i$)$;

$\}$

read$\_$messages$($argv$[2],$ output$)$;

fclose$($output$)$;

printf$("$Complete$.$ Output file written to output$\_$ls$.$txt$.$

$")$;

return $0$;

$\}$