#include<stdio.h>
#include<stdlib.h>

int mian (void)
{
    FILE *fp,*dfp;
    char c1[100],c2;
    if(fp=fopen("150510134-彭霞-1-doc","wt")==NULL)
    {
        PRINTF("打开文件出错");
        system("pause");
        exit(1);
    }
    puts("输入一串字符");
    gets(c1);
    fputs(c1,fp);
    fclose(fp);
    if(dfp=fopen("150510134-彭霞-1-doc","rt")==NULL)
    {
        printf("文件出错");
        system("pause");
        exit(2);
    }
    c2=fgetc(dfp);
    while(c2!=EOF)
    {
        
        putchar(c2);
        c2=fgetc(dfp);
    }
    fclose(dfp);
    system("pause");
    return 0;
}
.obj : error LNK2001: unresolved external symbol _PRINTF
LIBCD.lib(crt0.obj) : error LNK2001: unresolved external symbol _main
Debug/文件.exe : fatal error LNK1120: 2 unresolved externals
执行 link.exe 时出错.

文件.exe - 1 error(s), 0 warning(s)

1.obj : error LNK2001: unresolved external symbol _PRINTF
Debug/DF.exe : fatal error LNK1120: 1 unresolved externals
执行 link.exe 时出错.

DF.exe - 1 error(s), 0 warning(s)
什么意思？？？