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

const int MAXLEN = 30;

void listfile(char *filename);

int main(void)
{
    char *filename = "D:\\temp\\zhang.bin";
    char name[30];
    size_t length = 0;
    int age = 0;
    char answer = 'y';

    FILE *pfile = fopen(filename,"wb+");

    do
    {
        fflush(stdin);

        printf("Enter a name less than %d characters:",MAXLEN);
        gets(name);

        printf("Enter the age of %s:",name);
        scanf(" %d",&age);

        length = strlen(name);
        fwrite(&length,sizeof(length),1,pfile);
        fwrite(name,sizeof(char),length,pfile);
        fwrite(&age,sizeof(age),1,pfile);

   
   
        printf("Do you want to enter another(y or n)?");
        scanf(" %c",&answer);
    }while (tolower(answer) == 'y');
   
    fclose(pfile);

    listfile(filename);
    return 0;

}

void listfile(char *filename)
{
    size_t length = 0;
    char name[30];
    int age = 0;
    char format[20];

    sprintf(format ,"\n%%-%ds Age:%%4d",MAXLEN);

    FILE *pfile = fopen(filename,"rb");
    printf("\nThe contents of %s are:",filename);


    while(fread(&length,sizeof(length),1,pfile));
    {
   
        if(length+1 > MAXLEN)
        {
            printf("\nName too long.");
            exit(1);
        }
        fread(name,sizeof(char),length,pfile);
        name[length+1] = '\0';
        fread(&age,sizeof(age),1,pfile);
        printf(format,name,age);
    }
    fclose(pfile);
}
编译可以通过，但执行却出现乱码，跪求大侠解决方案。

犯晕，只是干嘛的。。。

你能不能把那个定义写清楚或者它的功能表达出来，我看求长度又看不像