格式符%02d中2d前面的前导符0表示输出数据时，若左边有多余位，则补0。利用这种输出格式，编程输出下面的信息。

#include <stdio.h>
typedef struct date{int year;int month;int day;
} DATE;
typedef struct student{long id;char name[10];char sex;DATE birthday;int score[4];
} STUDENT;
int main()
{STUDENT stu2 = {100310121,"王刚",'M', {1991,5,19}, {72,83,90,82}};printf("stu2: %ld %s %c %d/%02d/%02d %d %d %d %d\n",stu2.id,stu2.name,stu2.sex,stu2.birthday.year,stu2.birthday.month,stu2.birthday.day,stu2.score[0],stu2.score[1],stu2.score[2],stu2.score[3] );return 0;
}

2是宽度很简单。如果整数不够2列就补上0