Generare grafuri partiale orientate

#include <iostream>
#include <fstream>
using namespace std;
ifstream f("date.txt");
int n,x[100],m,nrsol=0;
struct arc{int ei,ef;};
arc v[100];

void citire(int &n,int &m)
{
int x1,x2;
    f>>n>>m;
for(int i=1;i<=m;i++)
    {f>>x1>>x2;
    v[i].ei=x1;
    v[i].ef=x2;
    }}

int valid(int k)
{return 1;}

int sol(int k)
{return k==m;}

void tipar(int k)
{
    nrsol++;
    for(int i=1;i<=k;i++)
if(x[i]==1)
cout<<"("<<v[i].ei<<" , "<<v[i].ef<<")"<<" ";
cout<<endl;}

void BKT()
{int k=1;
x[k]=-1;
while(k!=0)
if(x[k]<1)
{x[k]=x[k]+1;
if(valid(k))
if(sol(k))
tipar(k);
else
{k++;
x[k]=-1;}}
else
k--;}

int main()
{ citire(n,m);
BKT();
cout<<endl<<nrsol;
return 0;}