Missile Game

Function Lab Programming Study

This program is based on a CS110 class assignment from a previous semester. It demonstrates many user defined functions. You can study this program to get a better understanding of how user defined functions can break a complex program into readable pieces.

Missile Game

The distance to the landing point of a a projectile, launched at an angle angle (in radians) with an initial velocity of velocity (in feet per second), ignoring air resistance, is given by the formula:

                        
                               velocity *  velocity * sin(2*angle)
         distance    =         __________________________________ 

                                             32.2

Use missile_game.cpp in the replit team project or copy the following code into your IDE:

//***********************************************************************
//
// CS 110 Assignment 8
//
// Author: Dr. Cory Butz
//
// This C++ program gives a user five chances to hit a target.
//
// Inputs: float - targetDistance
//         float - launcherAngle
//         float - missileVelocity
//
// Outputs: int - shotNumber
//          float - targetDistance
//          float - launcherAngle
//          float - missileVelocity
//          float - missileDistance
//          float - distance between targetDistance and missileDistance
//
// Main Algorithm:
//                 Input distance to target
//                 Calculate winning range
//                 User has 5 shots
//                      input launcher angle in degrees
//                      input missile velocity
//                      convert launcher angle from degrees to radians
//                      calculate how far the missile travelled
//                      provide user feedback for the next shot
//                 Print appropriate win/lose message
//
//***********************************************************************

#include <iostream>
#include <cmath>
#include <iomanip>

using namespace std;

float getTargetDistance();
float calcWinningRange( float );
float getLauncherAngle();
float degreesToRadians( float );
float getMissileVelocity();
float calcMissileDistance( float, float );
void  printSummary( int, float, float, float, float);

int main()
{
     float targetDistance = 0.0;	// distance to target
     float winningRange = 0.0;		// within 0.1%
     float launcherAngle = 0.0;		// the launch angle in degrees
     float missileVelocity = 0.0;	// in feet per second
     float launcherRadians = 0.0; 	// the launch angle in radians
     float missileDistance = 0.0;	// distance the missile travelled
     bool  hit = false;		  	// flag for final message

// input distance to target
     targetDistance = getTargetDistance();

// the player can miss the target by 0.1%
     winningRange = calcWinningRange(targetDistance);

// player has 5 attempts to hit the target
     for(int shotNumber = 1; shotNumber <= 5; shotNumber++)
     {

// input launcher angle in degrees
          launcherAngle = getLauncherAngle();

// input the velocity of the missile
          missileVelocity = getMissileVelocity();

// convert launcher angle from degrees to radians
          launcherRadians = degreesToRadians(launcherAngle);

// calculate how far the missile travelled
          missileDistance = calcMissileDistance(launcherRadians, missileVelocity);

// output some feedback to the user to help for the next shot
          printSummary(shotNumber, targetDistance, launcherAngle,
                       missileVelocity, missileDistance);

// was the missile close enough to the target to win?
          if ( fabs(missileDistance - targetDistance) <= winningRange )
  	     {
	       hit = true;	// yes, set flag
	       break;		// and exit the for loop
          }
     }

// Did the player win?
     if ( hit == true )
          cout << "Hit! You win the game!\n";
     else
          cout << "Game Over. Play again.\n";

return 1;
}

//************************************************************************

float getTargetDistance()

// Input the distance to the target

{
     float distance = 0.0;

while ( distance <= 0.0 )
     {
          cout << "\nTarget distance in feet must be greater than zero."
               << "\nEnter target distance: ";
          cin >> distance;
     }

return distance;
}

//************************************************************************

float getLauncherAngle()

// Input the angle of the launcher in degrees

{
     float angle = 0.0;

while ( angle <= 0.0 || angle >= 90.0 )
     {
          cout << "\nThe launcher angle in degrees must be greater than zero and less than ninety."
               << "\nEnter launcher angle: ";
          cin >> angle;
     }

return angle;
}

//************************************************************************

float getMissileVelocity()

// Input a positive missile velocity in feet per second.

{
     float velocity = 0.0;

while ( velocity <= 0.0 )
     {
          cout << "\nThe missile velocity (in feet per second) "
               << "must be greater than zero."
               << "\nEnter missile velocity: ";
          cin >> velocity;
     }

return velocity;
}

//************************************************************************

float calcWinningRange( float targetDistance )

// the player is allowed to miss by 0.1%

{
     return (targetDistance * 0.001);
}

//************************************************************************

float degreesToRadians( float launcherAngle )

// convert degrees into radians

{
     return (launcherAngle * 3.14159265 / 180.0);
}

//************************************************************************

float calcMissileDistance( float radians, float velocity )

// Determine how far the missile travelled

{
     return ((velocity * velocity)  * sin(2 * radians) / 32.2);
}

//************************************************************************

void  printSummary( int shotNumber, float targetDistance, float launcherAngle,
                  float missileVelocity, float missileDistance)

// Provide the player with some feedback to help with the next shot

{
     cout << "\n***********************************************************\n"
          << "Shot Number: " << shotNumber << endl
          << "Target Distance: " << targetDistance << endl
          << "Launcher Angle: " << launcherAngle << endl
          << "Missile Velocity: " << missileVelocity << endl
          << "Missile Distance: " << missileDistance << endl;

if ( missileDistance <= targetDistance )
          cout << "\nThe missile landed "
               << targetDistance - missileDistance
               << " feet short of the target.\n";
     else
          cout << "\nThe missile landed "
               << missileDistance - targetDistance
               << " feet past the target.\n";
     cout << "***********************************************************\n";
}

This program first asks the user to enter the distance to a target.
The user then enters the angle and velocity for launching a projectile.
If the projectile comes within 0.1% of the distance to the target, the user wins the game.
If the projectile doesn't come close enough, the user is told how far off the projectile is and is allowed to try again.
If there isn't a winning input after five tries, then the user loses the game.
To simplify input for the user, your program should allow the angle to be input in degrees. The formula for converting degrees to radians is
```
radians = degrees * 3.14159265 / 180.0
```

Each of the formulas in this problem should be implemented as a C++ value-returning function.

The sample output of the program should look like the following:


Script on hercules[1]% missile

The distance to the target (in feet) must be > zero.
Enter target distance: 62.9

The launcher angle (in degrees) must be in-between zero and ninety.
Enter launcher angle: 45

The missile velocity (in feet per second) must be greater than zero.
Enter missile velocity: 45

***********************************************************
Shot Number: 1
Target Distance: 62.9
Launcher Angle: 45
Missile Velocity: 45
Missile Distance: 62.8882

The missile landed 0.0118027 feet short of the target.
***********************************************************
Hit! You win the game!
Script on hercules[2]% exit
exit

Script on hercules[1]% missile

The distance to the target (in feet) must be > zero.
Enter target distance: 0

The distance to the target (in feet) must be > zero.
Enter target distance: 62

The launcher angle (in degrees) must be in-between zero and ninety.
Enter launcher angle: 0

The launcher angle (in degrees) must be in-between zero and ninety.
Enter launcher angle: 90

The launcher angle (in degrees) must be in-between zero and ninety.
Enter launcher angle: 76

The missile velocity (in feet per second) must be greater than zero.
Enter missile velocity: -2

The missile velocity (in feet per second) must be greater than zero.
Enter missile velocity: 23

***********************************************************
Shot Number: 1
Target Distance: 62
Launcher Angle: 76
Missile Velocity: 23
Missile Distance: 7.71275

The missile landed 54.2873 feet short of the target.
***********************************************************

The launcher angle (in degrees) must be in-between zero and ninety.
Enter launcher angle: 78

The missile velocity (in feet per second) must be greater than zero.
Enter missile velocity: 43

***********************************************************
Shot Number: 2
Target Distance: 62
Launcher Angle: 78
Missile Velocity: 43
Missile Distance: 23.3558

The missile landed 38.6442 feet short of the target.
***********************************************************

The launcher angle (in degrees) must be in-between zero and ninety.
Enter launcher angle: 21

The missile velocity (in feet per second) must be greater than zero.
Enter missile velocity: 89

***********************************************************
Shot Number: 3
Target Distance: 62
Launcher Angle: 21
Missile Velocity: 89
Missile Distance: 164.602

The missile landed 102.602 feet past the target.
***********************************************************

The launcher angle (in degrees) must be in-between zero and ninety.
Enter launcher angle: 54

The missile velocity (in feet per second) must be greater than zero.
Enter missile velocity: 76

***********************************************************
Shot Number: 4
Target Distance: 62
Launcher Angle: 54
Missile Velocity: 76
Missile Distance: 170.599

The missile landed 108.599 feet past the target.
***********************************************************

The launcher angle (in degrees) must be in-between zero and ninety.
Enter launcher angle: 35

The missile velocity (in feet per second) must be greater than zero.
Enter missile velocity: 75

***********************************************************
Shot Number: 5
Target Distance: 62
Launcher Angle: 35
Missile Velocity: 75
Missile Distance: 164.154

The missile landed 102.154 feet past the target.
***********************************************************
Game Over. Play again.
Script on hercules[2]% exit

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