这个问题，使得人们仿佛又回到了字符界面的时代。

问题链接：UVA12412 A Typical Homework (a.k.a Shi Xiong Bang Bang Mang)。

题意简述：学生成绩有关数据的增删统计等（具体内容参见原问题）。

问题分析：使用一个结构类型数组存储数据，对其中数据进行操作。字符时代的软件似乎就是这样，只是少了用文件来存储最终的结果。

程序说明：（略）。

AC的C语言程序如下：

/* UVA12412 A Typical Homework (a.k.a Shi Xiong Bang Bang Mang) */#include <stdio.h>
#include <string.h>
#include <memory.h>#define MAXN 100
#define MAXLEN1 10
#define MAXLEN2 20#define EPS 1e-5struct student {char sid[MAXLEN1+1];int cid;char name[MAXLEN2+1];int score[5];int removed;
} all[MAXN+1];
int scount;void output_menu()
{printf("Welcome to Student Performance Management System (SPMS).\n\n");printf("1 - Add\n");printf("2 - Remove\n");printf("3 - Query\n");printf("4 - Show ranking\n");printf("5 - Show Statistics\n");printf("0 - Exit\n\n");
}void add()
{int dflag, i;for(;;) {printf("Please enter the SID, CID, name and four scores. Enter 0 to finish.\n");struct student in;scanf("%s", in.sid);if(strcmp(in.sid, "0") == 0)break;scanf("%d", &in.cid);scanf("%s", in.name);scanf("%d", &in.score[1]);scanf("%d", &in.score[2]);scanf("%d", &in.score[3]);scanf("%d", &in.score[4]);dflag = 0;for(i=0; i<scount; i++)if(!all[i].removed && strcmp(in.sid, all[i].sid)==0) {printf("Duplicated SID.\n");dflag = 1;continue;}if(!dflag) {in.score[0] = in.score[1] + in.score[2] + in.score[3] + in.score[4];in.removed = 0;all[scount++] = in;}}
}int rank(int x)
{int t = all[x].score[0];int high=0, i;for(i=0; i<scount; i++)if(!all[i].removed && all[i].score[0] > t)high++;return high + 1;
}void queryremove(int flag)
{char s[MAXLEN1+1];int i;for(;;) {printf("Please enter SID or name. Enter 0 to finish.\n");scanf("%s", s);if(strcmp(s, "0") == 0)break;int rcount = 0;for(i=0; i<scount; i++) {if(!all[i].removed && (strcmp(s, all[i].sid) == 0 || strcmp(s, all[i].name) == 0)) {if(flag){printf("%d %s %d %s %d %d %d %d %d %.2f\n", rank(i), all[i].sid, all[i].cid, all[i].name,all[i].score[1], all[i].score[2], all[i].score[3], all[i].score[4], all[i].score[0], all[i].score[0]/4.0+EPS);}else{all[i].removed = 1;rcount++;}}}if(!flag)printf("%d student(s) removed.\n", rcount);}
}void output_score(int id, int type)
{int sum=0, count1=0, count2=0, i;for(i=0; i<scount; i++) {if(!all[i].removed && (id == 0 || all[i].cid == id)) {sum += all[i].score[type];if(all[i].score[type] >= 60)count1++;elsecount2++;}}printf("Average Score: %.2f\n", count1+count2 == 0 ? 0 : sum*1.0/(count1+count2)+EPS);printf("Number of passed students: %d\n", count1);printf("Number of failed students: %d\n", count2);printf("\n");
}void statistics()
{int id, i, j;printf("Please enter class ID, 0 for the whole statistics.\n");scanf("%d", &id);printf("Chinese\n");output_score(id, 1);printf("Mathematics\n");output_score(id, 2);printf("English\n");output_score(id, 3);printf("Programming\n");output_score(id, 4);printf("Overall:\n");int okcount[5];memset(okcount, 0, sizeof(okcount));for(i=0; i<scount; i++) {if(!all[i].removed && (id == 0 || all[i].cid == id)) {int ok = 0;for(j=1; j<=4; j++)if(all[i].score[j] >= 60)ok++;okcount[ok]++;}}printf("Number of students who passed all subjects: %d\n", okcount[4]);printf("Number of students who passed 3 or more subjects: %d\n", okcount[3]+okcount[4]);printf("Number of students who passed 2 or more subjects: %d\n", okcount[2]+okcount[3]+okcount[4]);printf("Number of students who passed 1 or more subjects: %d\n", okcount[1]+okcount[2]+okcount[3]+okcount[4]);printf("Number of students who failed all subjects: %d\n", okcount[0]);printf("\n");
}int main(void)
{int choice;scount = 0;for(;;) {output_menu();scanf("%d", &choice);if(choice == 1)add();else if(choice == 2)queryremove(0);else if(choice == 3)queryremove(1);else if(choice == 4)printf("Showing the ranklist hurts students' self-esteem. Don't do that.\n");else if(choice == 5)statistics();else if(choice == 0)break;}return 0;
}