Array values not printing correctly - c++

Question

I wrote this code for printing the productions after eliminating left recursion.And also i stored these output productions in "all" array. when i print this array, only the last values are being printed with blank lines in the initial rows.How to resolve this problem?
#include<iostream>
#include<cstring>
using namespace std;
class production
{
private:
char lhs;
char rhs[10][10],nr[10][10],rs[10][10],all[30][30];
int noa,m;
public:
production()
{
noa=0;m=0;
for(int i=0;i<30;i++)
for(int j=0;j<30;j++)
all[i][j]='\0';
}
void makeprod(char *str)
{
noa=0;
for(int i=0;i<30;i++)
for(int j=0;j<30;j++)
rhs[i][j]='\0';
lhs=str[0];
char r[20];
strcpy(r,str+3);
int j=0;
for(int i=0;r[i]!='\0';i++)
{
if(r[i]!='/')
rhs[noa][j++]=r[i];
else
{
rhs[noa++][j]='\0';
j=0;
}
}
noa++;
}
void checks(string sr)
{
for(int i=0;i<30;i++)
for(int j=0;j<30;j++)
rs[i][j]=nr[i][j]='\0';
int ct=0,k=0,l=0;
for(int i=0;i<noa;i++)
{
if(lhs==rhs[i][0])
{
strcat(rhs[i],sr.c_str());
strcpy(rs[k],rhs[i]+1);
k++;
}
else
{
strcpy(nr[l],rhs[i]);
strcat(nr[l],sr.c_str());
l++;
}
}
if(l==noa)
{
cout<<lhs<<"->";
for(int i=0;i<noa;i++)
cout<<rhs[i]<<" ";
cout<<"\n";
all[m][0]=lhs;
strcat(all[m],"->");
for(int i=0;i<noa;i++)
{
strcat(all[m],rhs[i]);
strcat(all[m],"/");
}
m++;
}
else
{
cout<<lhs<<"->";
for(int i=0;i<l;i++)
cout<<nr[i]<<" ";
p.all[m][0]=lhs;
strcat(all[m],"->");
for(int i=0;i<l;i++)
{
strcat(all[m],nr[i]);
strcat(all[m],"/");
}
m++;
cout<<"\n"<<sr<<"->";
for(int i=0;i<k;i++)
cout<<rs[i]<<" ";
cout<<" e\n";
all[m][0]=lhs;
strcat(all[m],"->");
for(int i=0;i<k;i++)
{
strcat(all[m],rs[i]);
strcat(all[m],"/");
}
m++;
}
cout<<"m= "<<m<<"\n";
for(int i=0;i<m;i++)
{
for(int j=0;all[i][j]!='\0';j++)
cout<<all[i][j];
cout<<"\n";
}
}
void display()
{
cout<<"m= "<<m<<"\n";
for(int i=0;i<m;i++)
{
for(int j=0;all[i][j]!='\0';j++)
cout<<all[i][j];
cout<<"\n";
}
}
};
int main()
{
production p;
char str[20][20];
string op[5]={"X","Y","Z","U","V"};
cout<<"enter no of productions\n";
int n,l=0;
cin>>n;
for(int i=0;i<n;i++)
{
cout<<"enter a production\n";
cin>>str[i];
p.makeprod(str[i]);
p.checks(op[l++]);
}
p.display();
return 0;
}