刚开始C ++：编译时未定义的符号错误 [英] Just started C++: Undefined Symbol error on Compile
问题描述
这是情况：
我刚刚开始我的第一个C ++类。我对C ++一无所知，尽管这是C ++类的介绍，老师已经为语言教了很多NO语法，只是我们已经知道的逻辑。
I just started my first C++ class. I know nothing about C++ and despite this being the an intro to C++ class, the teacher has taught pretty much NO syntax for the language, just logic that we already know.
现在他给了我们一个程序描述，并说，写，哈哈。我理解的逻辑罚款，但正如我所说，我不知道C ++。因此，我首先在java（我知道）写它，然后一旦我在java中工作，我试图将其编码到C ++。
Now he gave us a program description and said, "write it, lol." I understand the logic fine, but as I said before, I know nothing about C++. Thus I wrote it first in java (which I do know), and then once I got it working in java, I tried to code it over to C++.
我编译时遇到以下错误
uxb3% g++ -o Race race.cc
Undefined first referenced
symbol in file
main /usr/local/gcc-4.1.1/bin/../lib/gcc/sparc-sun-solaris2.10/4.1.1/crt1.o
ld: fatal: Symbol referencing errors. No output written to Race
collect2: ld returned 1 exit status
有人可以帮助我
这是我的代码在.txt文件中：
http://rapidshare.com/files/195742284/race.txt.html
Here is my code in a .txt file: http://rapidshare.com/files/195742284/race.txt.html
和此处它在复制粘贴中：
and here it is in a copy paste:
#include <cstdlib>
#include <ctime>
#include <iostream>
#include <string>
using namespace std;
class Race
{
void main()
{
executeRace();
}
int randomMove()
{
srand(time(NULL));
int randomInt = rand() % 100 + 1;
return randomInt;
}
void executeRace()
{
int rabbitPosition = 1;
int turtlePosition = 1;
cout << "BANG!!!" << endl << "AND THEY'RE OFF!!!";
while (rabbitPosition <=70 && turtlePosition <=70)
{
printPositions(rabbitPosition, turtlePosition);
turtlePosition = turtleMoveSquares(turtlePosition);
rabbitPosition = rabbitMoveSquares(rabbitPosition);
}
printWinner(rabbitPosition, turtlePosition);
tie(rabbitPosition, turtlePosition);
}
int turtleMoveSquares(int tPosition)
{
int turtleMove = randomMove();
if(turtleMove >=1 && turtleMove <= 40)
tPosition = tPosition + 4;
if(turtleMove >= 41 && turtleMove <= 50 )
tPosition = tPosition - 2;
if(turtleMove >=51 && turtleMove <=100)
tPosition = tPosition + 2;
if(tPosition < 1)
tPosition = 1;
return tPosition;
}
int rabbitMoveSquares(int rabbitPosition)
{
int rabbitMove = randomMove();
if(rabbitMove >=1 && rabbitMove <= 25)
rabbitPosition = rabbitPosition;
if(rabbitMove >=26 && rabbitMove <= 55)
rabbitPosition = rabbitPosition + 10;
if(rabbitMove >=56 && rabbitMove <=60)
rabbitPosition = rabbitPosition - 15;
if(rabbitMove >=61 && rabbitMove <= 90)
rabbitPosition = rabbitPosition + 5;
if(rabbitMove >=90 && rabbitMove <=100)
rabbitPosition = rabbitPosition - 3;
if(rabbitPosition < 1)
rabbitPosition = 1;
return rabbitPosition;
}
void printPositions(int rabbitPositions, int turtlePositions)
{
int turtleCount;
int rabbitCount;
int endCount;
if(rabbitPositions == turtlePositions && rabbitPositions != 1)
{
turtleCount = 1;
while(turtleCount < turtlePositions)
{
cout << "-";
turtleCount = turtleCount+1;
}
cout << "OUCH!";
}
else
{
turtleCount = 1;
rabbitCount = 1;
endCount=1;
if(turtlePositions < rabbitPositions)
{
while(turtleCount < turtlePositions)
{
cout << "-";
turtleCount = turtleCount+1;
}
cout << "T";
while(rabbitCount < (rabbitPositions - turtlePositions))
{
cout << "-";
rabbitCount = rabbitCount+1;
}
cout << "H";
}
if(rabbitPositions < turtlePositions)
{
while(rabbitCount < rabbitPositions)
{
cout << "-";
rabbitCount = rabbitCount+1;
}
cout << "H";
while(turtleCount < (turtlePositions - rabbitPositions))
{
cout << "-";
turtleCount = turtleCount+1;
}
cout << "T";
cout << "\n";
}
}
}
void printWinner(int rabbitPosition, int turtlePosition)
{
if(turtlePosition >= 70 && rabbitPosition < 70)
{
cout << "TORTOISE WINS!!! YAY!!!\n";
}
else if(rabbitPosition >=70 && turtlePosition < 70)
{
cout << "Hare wins. Yuch.\n";
}
else if(rabbitPosition >=70 && turtlePosition >=70)
{
cout << "It's a tie\n";
}
}
void tie(int turtlePosition, int rabbitPosition)
{
if(rabbitPosition >=70 && turtlePosition >=70)
executeRace();
}
};
推荐答案
/ code>未定义，这是正确的。 C和C ++需要一个名为 main 的独立函数，它返回 int 。使用名为 main 的方法拥有类是不够的;编译器只关心独立的一个。
It's complaining about main being undefined, and it's right. C and C++ require a standalone function named main which returns int. It is not sufficient to have a class with a method named main; the compiler only cares about the standalone one.
另一件要记住的是，类中的成员的默认可见性类型是私人。或者更改你的类使用 struct - 这是两者之间的唯一区别 - 或指定公开的可见性：
Another thing to remember is that the default visibility for members in a class type is private. Either change your class to use struct — that's pretty much the only difference between the two — or specify public visibility:
class Race {
public:
void main() { ... }
};
然后你可以调用 main 你的类：
Then you can call the main function from your class:
int main() {
Race race;
race.main();
return EXIT_SUCCESS;
}
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