How to fix this string validation (Telephone directory system) - c++

Question

Im talking about the string validation in void enter() , what im trying to do is create a system , where if someone accidentally puts a number in Enter name field , they need to write it again
im just not being able to solve this string validation at all.
I tried something like
after cout<<"Enter name";
for(int i=0;i<strlen(name);i++)
{
gets(name);
if(isalpha(name[i]))
cout<<"There is a number in the input , try again";
}
include<fstream.h>
include<stdio.h>
include<conio.h>
include<string.h>
include<stdlib.h>
class Directory
{
char name[20];
char num[30];
char address[50];
public:
void enter()
{
cout<<"Enter name: "<<endl;
gets(name);
cout<<"Enter number: "<<endl;
gets(num);
cout<<"Enter address: "<<endl;
gets(address);
}
it did work , but if I enter a name "mar3", now i have to enter Mark four times for it to take the record.

Answer 1

I think this is what you want to do. You want to reenter the name untill it meets your requrement.
bool validate(char name[])
{
for(int i=0;i<strlen(name);i++)
if(isalpha((unsigned char)name[i]))
{
cout<<"There is a number in the input , try again";
return 0;
}
return 1;
}
and while reading name do this.
gets(name);
while(!validate(name))
{
gets(name);
}
UPD :
use string and getline to read.
#include<fstream>
#include<cstdio>
#include<cstring>
#include<stdlib.h>
#include<stdio.h>
#include<iostream>
using namespace std;
bool validate(string name)
{
for(int i=0;i<name.length();i++)
if(isalpha(name[i]))
{
cout<<"There is a number in the input , try again\n";
return 0;
}
return 1;
}
class Directory
{
string name,num,address;
public:
void enter()
{
cout<<"Enter name: "<<endl;
getline(cin,name);
while(!validate(name))
{
getline(cin,name);
}
cout<<"Enter number: "<<endl;
getline(cin,num);
cout<<"Enter address: "<<endl;
getline(cin,address);
}
};
here is you want to also limit the length of the name or number you can make another validator for that