How to make search program in phone book by number

[oninoor]

// Phonebook project
//===============================

#include <iostream>
#include <conio.h>
#include <string>
using namespace std;


//prototypes
void printline(char, int);
bool name_valid(string);
bool mob_valid(string);

class contact
{
string name;
string mob;

public:
//Initialize the contact by a default value
contact(): name(""), mob("")
{}

// Shows all contacts
bool show()
{
if(name != "")
{
cout << name << "\t" << mob << endl;
return 1; //Indicates success
}
else
return 0; //Indicates failure
}

//Search
bool show(string search_term)
{
if(search_term == name)
{
cout << name << "\t" << mob << endl;
return 1;
}
else
return 0;
}

//Checks whether the name exists or not
bool name_exists(string tname)
{
if(tname == name)
return 1;
else
return 0;
}

//The contact object is initialized by valid values
bool add(string new_name, string new_mob)
{
if(name=="")
{
name = new_name;
mob = new_mob;
return 1; // Success
}
else
return 0; // Failure

}

//Edits the contact details
bool edit(string);

//Sets the contact details to default values
//That is, the contact details are thus erased
bool erase(string new_name)
{
if(new_name==name)
{
name = "";
mob = "";
return 1;
}
else
return 0;
}
};


//Edits the contact
bool contact :: edit(string new_name)
{
string new_mob;
if(new_name==name)
{
cout << "Enter new name: "; cin >> new_name;
cout << "Enter new mobile no: "; cin >> new_mob;

name = new_name;
mob = new_mob;
return 1;
}
else
return 0;
}
int main()
{
contact person[100];

string temp_name, temp_mob;
int choice, i, counter;
bool flag;
bool cancel_flag;

cout << "**** PHONEBOOK ******" << endl;


do
{
cout << "\n\n\n";
printline('-', 20);
cout << "1. Memasukkan Data" << endl
<< "2. Menampilkan Data" << endl
<< "3. Mencari Data Berdasar Nama" << endl
<< "4. Mencari Data Berdasar No. Telfon" << endl
<< "5. Keluar" << endl
<< "Masukkan Pilihan Anda : ";
cin >> choice;

system("cls");
printline('-', 20);
cancel_flag = 0;
flag = 0;
counter = 0;

switch (choice)
{
case 1:
cout << "Add New Contact\t\t\t\tpress $ to cancel" << endl;
printline('-', 20);
counter = 0;

//Berulang hingga nama dan no benar
do
{
flag = 0;
if (counter)
cout << "Try again\t\t\t\tpress $ to cancel"
<< endl;

//counts how many times the do-while loop executes
counter++;

cout << "Name: "; cin >> temp_name;

//Cancel operation
if (temp_name == "$")
{
cancel_flag = 1;
break;
}
cout << "Mobile No.: "; cin >> temp_mob;

//Cancel operation
if (temp_mob == "$")
{
cancel_flag = 1;
break;
}

//Check whether name exists
for (i = 0; i<100; i++)
if (person[i].name_exists(temp_name))
{
cout << "Kontak sudah ada!"
"Masukkan nama lain."
<< endl;
flag = 1;
break;
}

} while (!name_valid(temp_name) ||
flag ||
!mob_valid(temp_mob));

if (cancel_flag)
{
system("cls");
break;
}


//Memasukkan kontak ke buku telfon
for (i = 0; i<100; i++)
if (person[i].add(temp_name, temp_mob))
{
cout << "Berhasil Menambah Kontak" << endl;
flag = 1;
break;
}

if (!flag)
cout << "Memory Kontak Penuh! Hapus Beberapa Kontak."
<< endl;
break;

case 2:
cout << "Menampilkan Kontak" << endl;
printline('-', 20);

for (i = 0; i<100; i++)
if (person[i].show())
flag = 1;

if (!flag)
cout << "Tidak ada kontak yang ditemukan!" << endl;
break;

case 3: //search contact by name
do
{
if (counter)
cout << "Coba lagi" << endl;
counter++;
cout << "Cari Nama : \t\t\t\tpress $ to cancel\n";
cin >> temp_name;

//Cancel Operation
if (temp_name == "$")
{
system("cls");
break;
}

for (i = 0; i<100; i++)
if (person[i].show(temp_name))
{
flag = 1;
break;
}

if (!flag)
cout << "Kontak tidak ditemukan" << endl;
} while (!flag);

break;

case 4: //search contact by number
do
{
if (counter)
cout << "Coba lagi" << endl;
counter++;
cout << "Cari Nomor : \t\t\t\tpress $ to cancel\n";
cin >> temp_mob;

//Cancel Operation
if (temp_mob == "$")
{
system("cls");
break;
}

for (i = 0; i<100; i++)
if (person[i].show(temp_name))
{
flag = 1;
break;
}

if (!flag)
cout << "Kontak tidak ditemukan" << endl;
} while (!flag);

break;

case 5:
return 0;
break;

}
} while (1);

_getch();
return 0;
}
//prints a line
void printline(char ch, int size)
{
for (int i = 0; i<size; i++)
cout << ch;
cout << "\n";
}


//Contact name validation
bool name_valid(string tname)
{

if (tname.size()>20)
{
cout << "Nama Salah!\nMasukkan Maks 20 Karakter dan Tanpa Spasi!"
<< endl;
return 0;
}
else if (tname == "")
{
cout << "Nama Salah!\nNama tidak boleh kosong!" << endl;
return 0;
}
else
return 1;
}

//mobile number validation
bool mob_valid(string tmob)
{
if (tmob.size()>13 || tmob.size()<10)
{
cout << "Nomor salah\n"
"Masukkan Nomor Antara 10 - 13 digit" << endl;
return 0;
}
else if (tmob == "")
{
cout << "No salah\n"
"Nomor tidak boleh kosong" << endl;
return 0;
}
else
return 1;
}


Hey guys, in case 3, it's for searching contact in phone book by name, and i have problem in case 4, it's for searching contact in phone book by number, can you give me the correct algorithm for my Case 4 plz, thankss.

[salem c]

http://www.cplusplus.com/articles/jEywvCM9/
Nobody wants to read 100's of lines of unformatted code.