#include<stdio.h>

 int main( void )
{
    void input( int *);
    void max_min_value( int * );
    void output( int * );

    int number[10];
    input( number );
    max_min_value( number );
    output( number );
   
    return (0);
}

void input( int number[] )
{
    int i;
    printf( "imput 10 numbers:" );
    for( i = 0; i < 10 ; i++ )
        scanf( "%d", &number[i] );
}

void max_min_value( int number[] )
{
    int *max,*min,*p,temp;

    max=min=number;
    for( p = number + 1; p  < number+10; p++ ){
        if( *p > *max){
            max = p;
        }
        else
            if( *p < *min ) min = p;

    }

    temp = number[0];
    number[0] = *min;
    *min = temp;
   
    if( max = number ) max=min;

    temp = number[9];
    number[9] = *max;
    *max = temp;
}

void output( int number[] )
{
    int *p;
    printf( "Now,they are:   " );
    for( p = number; p < number + 9; p++)
        printf("%d", *p);
    printf( "\n" );
}


编译以后出现下面的错误提示，到底是什么原因呀
--------------------Configuration: mytextpr - Win32 Debug--------------------
Linking...
mytext1.obj : error LNK2001: unresolved external symbol "void __cdecl output(int *)" (?output@@YAXPAH@Z)
mytext1.obj : error LNK2001: unresolved external symbol "void __cdecl max_min_value(int *)" (?max_min_value@@YAXPAH@Z)
mytext1.obj : error LNK2001: unresolved external symbol "void __cdecl input(int *)" (?input@@YAXPAH@Z)
Debug/mytextpr.exe : fatal error LNK1120: 3 unresolved externals
Error executing link.exe.

mytextpr.exe - 4 error(s), 0 warning(s)

这段代码是谭浩强C程序设计指针那张的一道题目呀

题目：输入10个整数，将其中最小的数与第一个数对换，把最大的数与最后一个数对换。