Program to find length, compare and concatenate the strings.

Program:-

#include<iostream.h>
#include<conio.h>
#include<stdio.h>
void findlength()
{
char str[30];
int l=0;
cout<<"\n Enter the string (size<=30) ";
gets(str);
while(str[l]!='\0')
{
l++;
}
cout<<"\n Length Of the given String is: "<<l<<endl;
}
void compare()
{
char str1[30], str2[30];
int l1=0,l2=0,i=0,flag=0;
cout<<"\n Enter the string1 (size<=30) ";
gets(str1);
while(str1[l1]!='\0')
{
l1++;
}
cout<<"\n Enter the string2 (size<=30) ";
gets(str2);
while(str2[l2]!='\0')
{
l2++;
}
if(l2!=l1)
{
cout<<"\n Strings are not Equal ";
}
else
{
for(i=0;i<l1;i++)
{
   if(str1[i]!=str2[i])
   {
flag=1;
break;
   }
}
if(flag==1)
{ cout<<"\n Strings are not Equal ";
}
else
{
cout<<"\n Strings are Equal ";
}
}
}
void concat()
{
char str1[30], str2[30];
int l1=0,l2=0,i=0,flag=0;
cout<<"\n Enter the string1 (size<=30) ";
gets(str1);
while(str1[l1]!='\0')
{
l1++;
}
cout<<"\n Enter the string2 (size<=30) ";
gets(str2);
while(str2[l2]!='\0')
{
l2++;
}
for(i=0;i<l2;i++)
{
str1[l1+i]=str2[i];
}
str1[l1+l2]='\0';
cout<<"\n The concatenated String is: ";
puts(str1);
}
void main()
{
clrscr();
cout<<"Enter your choice \n \t1.Find length of string\n\t"
"2.Compare two Strings \n\t3.Concatenate two strings\n\t4.Exit \n";
char ch;
cin>>ch;
do
{
if(ch=='1')
findlength();
if(ch=='2')
compare();
if(ch=='3')
concat();
cout<<"Enter your choice \n \t1.Find length of string\n\t"
"2.Compare two Strings \n\t3.Concatenate two strings\n\t4.Exit \n";
cin>>ch;
}while(ch!='4');
getch();
}

Output:-