C++ Language Use functions to solve all problems in the mentioned assignment

Following are the program to this question:

Q1:

#include <iostream> //including header file

using namespace std;

int main() //defining main method

{

   int m,n,i; //defining integer variable

   cout<<"Enter starting value: "; //print message

   cin>>m; //input m variable value

   cout<<"Enter ending value: ";//print message

   cin>>n;//input n variable value

   for(i=m;i<=n;i++) //defining loop to count even number  

   {

       if(i%2==0) //check even number condition

       {

           cout<<i<<" "; //print value

       }

   }

   return 0;

}

Q2:

#include<iostream> //include header file

using namespace std;

void menu() //define method menu

{

cout<<"Enter 1 for print your name and id: "<<endl; //print message

cout<<"Enter 2 for sum of odd numbers from 1 to 20: "<<endl;//print message

cout<<"Enter 3 for reverse of any number: "<<endl;//print message

cout<<"Enter 4 for exit"<<endl;//print message

}

void findsum() //define method findsum

{

int s=0,i; //defining integer variable

for(i=1;i<=20;i++) //defining loop to count odd number  

{

s=s+i; //add numbers

}

cout<<"Odd number sum from 1 to 20: "<<s; //print value

}

void revers() //defining method revers

{

int n,r,rev=0; //defining integer variable

cout<<"enter any number: "; //print message

cin>>n; //input value

while(n!=0) //define loop to reverse value

{

r=n%10; //store value in r variable

rev=(rev*10)+r; //add reverse value

n=n/10; //divide digit

}

cout<<"The reverse of a given number is: "<<rev; //print reverse value

}

int main() //defining main method

{

int c,rn; //defining integer variable

char n[30]; // defining char variable

menu(); //calling menu method

cout<<"Enter your selected choice: "<<endl; //print message

cin>>c; //input value in char variable

switch(c) //defining switch

{

   //defining case

case 1: cout<<"Enter your name: "<<endl; //print message for input name and id  

       cin>>n;//input name

       cout<<"Enter registration number: "<<endl; //print message  

       cout<<"Name: "<<n<<endl; // print name value

       cout<<"Registration number: "<<rn<<endl; // print id value

   break;

case 2: findsum(); //calling findsum method

   break;

case 3: revers(); //calling reverse method

   break;

case 4: exit(1); // calling exit method

   break;

default: cout<<"please enter valid choice"; //defining default choice

   break;

}

return 0;

}

Q3:

#include <iostream>//defining header file

using namespace std;

void reverse() //defining method readInput

{

  char x; //defining char variable

  cout<<"Enter a character: "; //print message

  cin>>x; //input value

  if(x=='.') //defining condition that check value is .  

   return; //using return keyword

  reverse(); //calling readInput method

  cout<<x; //print value

}

int main() //defining main method

{

  reverse(); //calling readInput method

return 0;    

}

Output:

please find the attachment.

Explanation:

Description of the given question as follows:

(a) oldest