没有语法错误，但是运行的时候有乱码。
#include<stdio.h>
#include<string.h>
struct date
{
    int month;
    int day;
    int year;
};
struct tongxunlu
{
    char name[10];
    char sex;
    char addr[10];
    int age;
    int num;
    long int tel;
    struct date birthday;
};
void shuru(struct tongxunlu a[],int n);
void xiugai(struct tongxunlu a[],int n);
void chaxun1(struct tongxunlu a[],int n);
void chaxun2(struct tongxunlu a[],int n);
void zengjia(struct tongxunlu a[],int n);
void paixu(struct tongxunlu a[],int n);
int main()
{
    int n,i;
    struct tongxunlu tong[20];
printf("请输入录入的学生人数n(n<=20): ");
    scanf("%d",&n);
shuru(tong,n);
    printf("the information: \n");
    printf("姓名      性别    住址       年龄     学号      电话            生日\n");
    for(i=0;i<n;i++)
        printf("%s,%c,%s,%d,%d,%ld,%d,%d,%d\n",tong[i].name,tong[i].sex,tong[i].addr,tong[i].age,tong[i].num,tong[i].tel,tong[i].birthday.month,tong[i].birthday.day,tong[i].birthday.year);
xiugai(tong,n);
    for(i=0;i<n;i++)   
printf("%s,%c,%s,%d,%d,%ld,%d,%d,%d\n",tong[i].name,tong[i].sex,tong[i].addr,tong[i].age,tong[i].num,tong[i].tel,tong[i].birthday.month,tong[i].birthday.day,tong[i].birthday.year);
printf("按学号查询: \n");
    chaxun1(tong,n);
printf("按成绩查询: \n");
    chaxun2(tong,n);
zengjia(tong,n);
    for(i=0;i<n;i++)
    printf("%s,%c,%s,%d,%d,%ld,%d,%d,%d\n",tong[i].name,tong[i].sex,tong[i].addr,tong[i].age,tong[i].num,tong[i].tel,tong[i].birthday.month,tong[i].birthday.day,tong[i].birthday.year);
    printf("按学号排序：\n");
paixu(tong,n);
    for(i=0;i<n;i++)
    printf("%s,%c,%s,%d,%d,%ld,%d,%d,%d\n",tong[i].name,tong[i].sex,tong[i].addr,tong[i].age,tong[i].num,tong[i].tel,tong[i].birthday.month,tong[i].birthday.day,tong[i].birthday.year);
    return 0;   
}
void shuru(struct tongxunlu a[],int n)
{
    int i;
    for(i=0;i<n;i++)
    {
        printf("请输入第%d个学生的信息（姓名、性别、地址、年龄、学号、电话号码、生日）: \n",i+1);
        scanf("%s,%c,%s,%d,%d,%ld, %d, %d, %d\n", a[i].name, &(a[i].sex), a[i].addr,&(a[i].age),&(a[i].num),&(a[i].tel), &(a[i].birthday.month), &(a[i].birthday.year), &(a[i].birthday.year));
    }
}
void xiugai(struct tongxunlu a[],int n)
{
    int k,b,i;
    printf("修改第%d个学生的信息\n",k);
    printf("%s,%c,%s,%d,%ld",&a[k].name,&a[k].sex,&a[k].addr,a[k].age,a[k].tel);
    printf("输入要修改的项目（姓名(1)、性别(2)、地址(3)、年龄(4)、学号(5)、电话(6)、生日(7)）: \n");
    scanf("%d",&b);
switch(b)
{
case 1:
    printf("输入新名字： \n");
    scanf("%s",a[i].name);
break;
case 2:
    printf("输入新性别： \n");
    scanf("%c",&(a[i].sex));  
break;
case 3:
    printf("输入新地址： \n");
    scanf("%s",a[i].addr);
break;
case 4:
    printf("输入新年龄： \n");
    scanf("%d",&(a[i].age));
break;
case 5:
    printf("输入新学号： \n");
    scanf("%d",&(a[i].num));
break;
case 6:
    printf("输入新电话： \n");
    scanf("%ld",&(a[i].tel));
break;
case 7:
    printf("输入新生日： \n");
    scanf("%d,%d,%d",&(a[i].birthday.month),&(a[i].birthday.day),&(a[i].birthday.year));
break;
}
}
void chaxun1(struct tongxunlu a[],int n)
{
    int newnum,i;
    printf("input the num: \n");
    scanf("%d",&newnum);
    for(i=0;i<n;i++)
    {
        if(newnum==a[i].num)
        printf("%s,%c,%s,%d,%d,%ld,%d,%d,%d",a[i].name,a[i].sex,a[i].addr,a[i].age,a[i].num,a[i].tel,a[i].birthday.month,a[i].birthday.day, a[i].birthday.year);
    }
}
void chaxun2(struct tongxunlu a[],int n)
{
    int newname,i;
    printf("input the name: \n");
    scanf("%s", &newname);
        if(strcmp(newname,a[i].name)==0)
    for(i=0;i<n;i++)
    {
        printf("%s,%c,%s,%d,%d,%ld,%d,%d,%d",a[i].name,a[i].sex,a[i].addr,a[i].age,a[i].num,a[i].tel,a[i].birthday.month,a[i].birthday.day, a[i].birthday.year);
    }
}
void zengjia(struct tongxunlu a[],int n)
{
    int i=n+1;
    printf("输入增加学生的信息：");
    scanf("%s,%c,%s,%d,%d,%ld,%d,%d,%d",a[i].name,&(a[i].sex),a[i].addr,&(a[i].age),&(a[i].num),&(a[i].tel),&(a[i].birthday.month),&(a[i].birthday.day), &(a[i].birthday.year));
}
void paixu(struct tongxunlu a[],int n)
{
    int i;
    int temp;

    for(i=0;i<n;i++)
        if(a[i].num>a[i+1].num)
        {
            temp=a[i].num;
            a[i].num=a[i+1].num;
            a[i+1].num=temp;
        }
        printf("%s,%c,%s,%d,%d,%ld,%d,%d,%d",a[i].name,a[i].sex,a[i].addr,a[i].age,a[i].num,a[i].tel,a[i].birthday.month,a[i].birthday.day, a[i].birthday.year);
}

没办法，老师要求的

呃。。。那应该怎样排