Program to print length of a string

#include<iostream>

#include<cstdio>

using namespace std;

int main()

{

char s[30];

int length=0,i;

cout<<"\n enter a string :";

gets(s);

for(i=0;s[i]!='\0';i++)

{

length++;

}

cout<<"length of string is"<<length;

}