C++ :: Console Application Should Be Like A Command Prompt

my C++ console application should be like a command prompt. There are "command lines" to execute in the command prompt.Here are my main prompts for spotlight:

Encode - New data entry
View - Read data from text file
Search - Find record from text file
Update - Save changes per text line from the existing text file
Delete - Delete lines from the text file

Now, I manage to do the tasks for Encode, View, and Search..But unfortunately, not in Update..I've been working this for a week already..

#include "stdafx.h"
#include "iostream"
#include "string"
#include "fstream"
using namespace std; //to omit the std
}

[code]....