C++ program

I have some code that is meant to prompt the user to enter 10 scores and choose one of three structures(if, while, or do-while) to then evaluate and display the name, score(%), and letter grade.  This is to be done using call by value.  I have spent hours on this and keep getting an external linker error.  What am I doing wrong?  Do I need all of these libraries?

#include <iostream.h>
#include <conio.h>
#include<ctype.h>
#include<iomanip.h>
#include<stdlib.h>
#include<math.h>

int Prompt_User_For_Selection(char);
int Service_Selection_Using_IfElse(char);
int Determine_LtrGrd_Using_Switch(float);


int main()
{
 char x;
 clrscr();                 //clear screen
 Prompt_User_For_Selection(x);
}
int Prompt_User_For_Selection(char start)
{
  char ans,y;
  do{
  clrscr();
  cout<<"STRUCTURE               SELECTION\n";
  cout<<"\n";
  cout<<"While                       W\n";
  cout<<"DO While                    D\n";
  cout<<"For                         F\n";
  cout<<"\n";
  cout<<"Enter Selection <Q to Quit>:\n";
  cout<<"\n\n\t";
  getch();
  cin>>ans;
  ans=toupper(ans);
  }while(ans!='W'&& ans!='D'&& ans!='F'&& ans!='Q');
   if (ans!='Q')
     return 0;
   else
    clrscr();
    cout<<"\n\n\tYou Selected to Quit BYE";
    cout<<"\n\n\tHit any key to exit:";
  getch();
  ans=start;
  y=Service_Selection_Using_IfElse(ans);
  return(y);
}
int Service_Selection_Using_IfElse(char ans2)
{
     char choice;
     int  final;
     int Execute_While_Loop();
     int Execute_Do_While_Loop();
     int Execute_For_Loop();


     char firstname[20];
     cout<<"Enter Your First Name:\n";
     cin>>firstname;
     char lastname[20];
     cout<<"Enter Your Last Name:\n";
     cin>>lastname;

     clrscr();

     if(choice=='W'){
      cout<<"\n\n\tYou Selected the While Structure\n";
      choice=ans2;
      Execute_While_Loop();

     }
     else
       if(choice=='D'){
        cout<<"\n\n\tYou Selected the Do While Structure\n";
        choice=ans2;
        Execute_Do_While_Loop();
       }
       else
        if(choice=='F'){
         cout<<"\n\n\tYou Selected the For Structure\n";
         choice=ans2;
         Execute_For_Loop();
        }

     cout<<"\n\n\n\n\tStudent Name:\t"<<firstname<<' '<<lastname<<endl<<endl;
     cout<<"\tGrade Average:\t"<<final<<"%"<<endl;
     final=Determine_LtrGrd_Using_Switch(choice);
     return(final);
     cout<<"\n\n\tHit any key to continue:";
     getch();
}
int Execute_While_Loop(float avg)
{
       int zz,result;
       int total,
           scoreCounter,
           score;
       total=0;
       scoreCounter=1;

       cout<<"\n\n\tEnter Score number"<<' '<<scoreCounter<<":\t";
       cin>>score;
       total=total+score;

       while(scoreCounter<10){
        while(score>100||score<0){
         cout <<"\n\n\tEnter Score number"<<' '<<scoreCounter<<":\t";
         cin>>score;
         }
        total=total+score;
        ++scoreCounter;
        cout<<"\n\n\tEnter Score number"<<' '<<scoreCounter<<":\t";
        cin>>score;
       }

       clrscr();
       zz=static_cast<float>(total)/scoreCounter;
       zz=avg;
       result=Determine_LtrGrd_Using_Switch(zz);
       return (result);
}
int Execute_Do_While_Loop(float avg2)
{
   int qq,result2;
   int total,
       scoreCounter,
       score;
   total=0;
   scoreCounter=1;

   cout<<"\n\n\tEnter Score number"<<' '<<scoreCounter<<":\t";
   cin>>score;
   total=total+score;
   do{
   cout <<"\n\n\tEnter Score number"<<' '<<scoreCounter<<":\t";
   cin>>score;
    do{
    total=total+score;
    ++scoreCounter;
    cout<<"\n\n\tEnter Score number"<<' '<<scoreCounter<<":\t";
    cin>>score;
    }while(scoreCounter<10&&score>=0&&score<=100);
   }while(score>100||score<0);
   clrscr();

   qq=static_cast<float>(total)/scoreCounter;
   qq=avg2;
   result2=Determine_LtrGrd_Using_Switch(qq);
   return result2;
}
int Execute_For_Loop(float avg3)
{
   int vv,result3;
   int total,
      score,
      scoreCounter;
   for(int total=0,scoreCounter=1;scoreCounter<=10;++scoreCounter,
        total=total+score){
      for(int scoreCounter;0>score||score>100;scoreCounter){
        cout<<"\n\n\tEnter Score number"<<' '<<scoreCounter<<":\t";
        cin>>score;
     }
      cout<<"\n\n\tEnter Score number"<<' '<<scoreCounter<<":\t";
      cin>>score;
   }

    clrscr();
    vv=static_cast<float>(total)/scoreCounter;
    vv=avg3;
    result3=Determine_LtrGrd_Using_Switch(vv);
    return(vv);
}
int Determine_LtrGrd_Using_Switch(float results)
{   int last;
    char LtrGrd;

    LtrGrd=floor(last*10+.5)/100;

    switch(LtrGrd){
      case 10:
      case 9:
       cout<<"\n\tLetter Grade:\t"<<"A";
       break;
      case 8:
       cout<<"\n\tLetter Grade:\t"<<"B";
       break;
      case 7:
       cout<<"\n\tLetter Grade:\t"<<"C";
       break;
      case 6:
       cout<<"\n\tLetter Grade:\t"<<"D";
       break;
      case 5:
       cout<<"\n\tLetter Grade:\t"<<"F";
       break;
    }
      last=results;
      return 0;
}
lickerAsked:
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RONSLOWConnect With a Mentor Commented:
Your prototype doesn't match the function.

eg.

you declare it as:
int Execute_Do_While_Loop();
     
but it is really:
int Execute_Do_While_Loop(float avg2)

Make them consistent.

And (as a metter of style), but you function declarations at the file-scope level (like you did with Prompt_User_for_Selection etc).

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RONSLOWCommented:
if it is a linker error then there is (probably) nothing wrong with the program (otherwise it wouldn't compile), but with how you are linking it (eg what libraries you are using).

Perhaps if you give us some details on the linker error we could help?
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lickerAuthor Commented:
It says:
[Linker Error] Unresolved external 'Execute_While_Loop()' referenced from C:\WINDOWS...
[Linker Error] Unresolved external 'Execute_Do_While_Loop()' referenced from C:\WINDOWS...
[Linker Error] Unresolved external 'Execute_For_Loop()' referenced from C:\WINDOWS...
0
 
computerpunkCommented:
Have you tried putting the function prototypes for the 3 functions at the top of the program ??
0
 
lickerAuthor Commented:
Thanx, I played with it and got it to work, though a little differently.
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