#include <stdio.h>
#define PAGELINE   20
#define PAGESPLINE 2
#define TXTWIDTH   30
#define TXTGAP     10

linecount()/*完成对输出行的计数和一页满后，输出空行*/
{
    static int pline=0;
    int i;

    if(++pline==PAGELINE)
    {
        for(i=0;i<PAGESPLINE;i++)/*输出一页后的空行*/
            printf("\n");
        pline=0;
    }
}

int readline(FILE *fpt)/*完成从指定的文件中读出一行多至30个字符并输出*/
{
    int c,cpos=0;

    while((c=fgetc(fpt))!='\n')
    {
        if(feof(fpt))
            break;/*文件结束推出循环*/
        printf("%c",c);
        cpos++;
        if(cpos>=TXTWIDTH)
            break;
    }
    return cpos;/*返回读入并输出的字符数*/
}

main()
{
    FILE *fpt1,*fpt2;
    char fname[120];/*存贮文件名*/
    int fill1,fill2;/*分别记录两个文件当前行读入并输出的字符数*/

    clrscr();
    printf("Enter file 1 name.\n");
    scanf("%s",fname);
    fpt1=fopen(fname,"r");/*打开文件1*/
    if(fpt1==NULL)
    {    printf("Can't open file %s.\n",fname);
        exit(1);
    }
    printf("Enter file 2 name.\n");
    scanf("%s",fname);
    fpt2=fopen(fname,"r");/*打开文件2*/
    if(fpt2==NULL)
    {    printf("Can't open file %s.\n",fname);
        fclose(fpt1);
        exit(2);
    }

    while(!feof(fpt1)||!feof(fpt2))/*在有文件还未结束时循环*/
    {
        fill1=fill2=0;
        if(!feof(fpt1)) fill1=readline(fpt1);/*在文件未结束时读文件*/
        printf("%*c",TXTWIDTH-fill1+TXTGAP,'');
        if(!feof(fpt2)) fill2=readline(fpt2);/*在文件未结束时读文件*/
        printf("%*c%2d\n",TXTWIDTH-fill2+4,'',fill1+fill2);
        linecount();/*调用行计数函数*/
    }
    puts("\n Press any key to quit...");
    getch();
}






为什么有问题？
上面显示

--------------------Configuration: 38 - Win32 Debug--------------------
Compiling...
38.C
C:\Users\zhshk\Desktop\220个经典C程序源码\038\38.C(42) : warning C4013: 'clrscr' undefined; assuming extern returning int
C:\Users\zhshk\Desktop\220个经典C程序源码\038\38.C(48) : warning C4013: 'exit' undefined; assuming extern returning int
C:\Users\zhshk\Desktop\220个经典C程序源码\038\38.C(63) : error C2137: empty character constant
C:\Users\zhshk\Desktop\220个经典C程序源码\038\38.C(65) : error C2137: empty character constant
C:\Users\zhshk\Desktop\220个经典C程序源码\038\38.C(69) : warning C4013: 'getch' undefined; assuming extern returning int
执行 cl.exe 时出错.

38.OBJ - 1 error(s), 0 warning(s)