Compiles but behaves wierdly - C++

[fallenone11]

I'm trying to write code for a function which would reformat code into a new format using a struct Entry[], and a sub array. Ultimately, the idea is to read the file in, but I can't figure out why this precursor isn't working

I need to read in as a string in format ("name 7-digitnumber") and turn it into ("name, 3digits-4digits"). The idea being to read many entries in this format, whereas this case is just one.

  #include <iostream>
#include <string>
using namespace std;


// Starting Format = joe   2388789
// Ending format = joe,   238-8789

typedef char Name[20];
typedef char Phone[8];
typedef char HOLDING[100];

struct Entry {     // Variable to hold all information
	HOLDING temp;
	Name name;
	Phone phone;
};

void reformat ( Entry L[], int n ); // n is how many entries there are

int main (){

	Entry L[50];
	int num = 20;
	

L[1].temp[1] = 'j';
L[1].temp[2] = 'o';
L[1].temp[3] = 'h';
L[1].temp[4] = 'n';
L[1].temp[5] = ' ';
L[1].temp[6] = ' ';
L[1].temp[7] = ' ';
L[1].temp[8] = 9;
L[1].temp[9] = 1;
L[1].temp[10] = 1;
L[1].temp[11] = 9;
L[1].temp[12] = 1;
L[1].temp[13] = 1;
L[1].temp[14] = 1;
L[1].temp[15] = 9;
L[1].temp[16] = 9;


reformat(L, num); 

  return 0;
}

void reformat ( Entry L[], int n) {
	
	for ( int i = 0; i <= n; i++) { // Initializing L[].phone and L[].name values
		
			for ( int z = 0; z >=30; z++) {
			
		 		if (L[i].temp[z] == '0' || L[i].temp[z] == '1' || L[i].temp[z] == '2' || L[i].temp[z] == '3' || L[i].temp[z] == '4' || L[i].temp[z] == '5' ) {
					L[i].phone[z] = L[i].temp[z];
				 }
		
				if (L[i].temp[z] == '6' || L[i].temp[z] == '7' || L[i].temp[z] == '8' || L[i].temp[z] == '9' ) {
					L[i].phone[z] = L[i].temp[z];
			 	}	
				
				else {
				L[i].name[z] = L[i].temp[z];
				}
			}	
			
			
			cout << L[i].name << ",   " <<  L[i].phone[0] << L[i].phone[1] << L[i].phone[2] << "-" << L[i].phone[3] << L[i].phone[4] << L[i].phone[5] << L[i].phone[6] << endl;
			
			
	}
	
	

 return;	
}

[JLBorges]

#include <iostream>
#include <string>
#include <cstring>

std::string re_format( std::string name_space_dddeeee )
{
    const auto sz = name_space_dddeeee.size() ;

    if( sz <= 9 ) return "string is too small" ;

    auto name_end = sz - 9 ;

    return name_space_dddeeee.substr(0,name_end) + // "name"
           name_space_dddeeee.substr( name_end, 5 ) + '-' + // ", ddd-"
           name_space_dddeeee.substr( name_end+5 ) ; // "eeee"

}

char* re_format( char cstr[], std::size_t n )
{
    const std::string str = re_format(cstr) ;
    return str.size() < n ? std::strcpy( cstr, str.c_str() ) : nullptr ;
}

int main()
{
    char cstr[128] = "Andrew R. Koenig, 1234567" ;
    if( re_format( cstr, sizeof(cstr) ) ) std::cout << cstr <<'\n' ;
}

http://coliru.stacked-crooked.com/a/ae7d1f83fbde793e