Answer:
A variable declaration is a name given to a memory location. It is the basic unit of storage in a program.
Line 2 or line 4 sorry if I’m wrong
Answer:
// Program is written in C++ Programming Language
// Comments are used for explanatory purpose
// Program starts here
#include<iostream>
using namespace std;
int main ()
{
// Declare Variable
int selection;
// Prompt user to make a selection of medium between air, water or steel.
cout<<"Make Selection"<<'\n'<<"Press 1 for Air"<<'\n'<<"Press 2 for Water"<<'\n'<<"Press 3 for Steel";
cin>>selection;
// Check for entry
if(selection == 1) {
cout<<"You selected Air"<<'\n';
cout<<"The distance travelled by sound wave in air is 1,125 feet in 1 second";
}
else if(selection == 2) {
cout<<"You selected Water"<<'\n';
cout<<"The distance travelled by sound wave in water is 4859 feet in 1 second";
}
else if(selection == 3) {
cout<<"You selected Steel"<<'\n';
cout<<"The distance travelled by sound wave in steel is 19554 feet in 1 second";
}
else
cout<<"Invalid Selection";
return 0;
}
