VS2010编译出错。。声明了啊，为什么还是出错

Question

#include
#include
#include
using namespace std;
void getRandomNumbers(short,short&,short&);
void displayProblem(char,short&,short&);
short calCorrectAnswer(char,short,short);
void main()
{
short gradeLevel=0;
char operation=' ';
short num1=0,num2=0,correctAnswer=0,userAnswer=0;
cout<<"Enter grade level(1 or 2)";
cin>>gradeLevel;
cout<<"Enter operation(a or s)";
cin>>operation;
operation=toupper(operation);
getRandomNumbers(gradeLevel,num1,num2);
displayProblem(operation,num1,num2);
cin>>userAnswer;
correctAnswer=calCorrectAnswer(operation,num1,num2);
if(userAnswer==correctAnswer)
cout<<"You are right.";
else
cout<<"Sorry,the correct answeris "<<correctAnswer<<endl;
}
void getRandomNumber(short level,short&firstNum,short&secondNum)
{
srand((unsigned int)time(NULL));
if(level==1)
{
firstNum=1+rand()%(10-1+1);
secondNum=1+rand()%(10-1+1);
}
else
{
firstNum=1+rand()%(100-10+1);
secondNum=1+rand()%(100-1+1);
}
}
void diaplayProblem(char operation,short&firstNum,short&secondNum)
{
if(operation=='A')
cout<<firstNum<<"+"<<secondNum<<"=";
else
{
if(firstNum<secondNum)
{
short temp=0;
temp=firstNum;
firstNum=secondNum;
secondNum=temp;
}
}
}
short calCorrectionAnswer(char operation,short firstNum,short secondNum)
{
short answer=0;
if(operation=='A')
answer=firstNum+secondNum;
else
answer=firstNum-secondNum;
return answer;
}

1>------ 已启动生成: 项目: 初, 配置: Debug Win32 ------
1>RandomQ.obj : error LNK2019: 无法解析的外部符号 "short __cdecl calCorrectAnswer(char,short,short)" (?calCorrectAnswer@@YAFDFF@Z)，该符号在函数 _main 中被引用
1>RandomQ.obj : error LNK2019: 无法解析的外部符号 "void __cdecl displayProblem(char,short &,short &)" (?displayProblem@@YAXDAAF0@Z)，该符号在函数 _main 中被引用
1>RandomQ.obj : error LNK2019: 无法解析的外部符号 "void __cdecl getRandomNumbers(short,short &,short &)" (?getRandomNumbers@@YAXFAAF0@Z)，该符号在函数 _main 中被引用
1>D:\VS2010\初\Debug\初.exe : fatal error LNK1120: 3 个无法解析的外部命令
========== 生成: 成功 0 个，失败 1 个，最新 0 个，跳过 0 个 ==========

Answer 1

函数名写错了，你声明的分别是：
void getRandomNumbers(short,short&,short&);
void displayProblem(char,short&,short&);
short calCorrectAnswer(char,short,short);
但是函数名是：
void getRandomNumber(short level,short&firstNum,short&secondNum)
void diaplayProblem(char operation,short&firstNum,short&secondNum)
short calCorrectionAnswer(char operation,short firstNum,short secondNum)
可以使用notepad++辅助检查。