问题遇到的现象和发生背景
遇到的现象和发生背景 运行后界面是空的
#include <stdio.h>
#include <stdlib.h>
#include <stdlib.h>
#include <string.h>
struct Student { //每个学生对应一个结构体
char ID[20];//学号
char Name[10];//姓名
float Mark1;//语文成绩
float Mark2;//数学成绩 //四个变量
float Mark3;//英语成绩
float Average1;//平均成绩
float Average2;//语文平均成绩
float Average3;//数学平均成绩
float Average4;//英语平均成绩
} students[1000];
int num = 0; //计数器
void Copy(struct Student *arr, int i, int j) {
strcpy(arr[i].ID, arr[j].ID); //strcpy()函数的简介：
strcpy(arr[i].Name, arr[j].Name);
arr[i].Mark1 = arr[j].Mark1;
arr[i].Mark2 = arr[j].Mark2;
arr[i].Mark3 = arr[j].Mark3;
arr[i].Average1 = arr[j].Average1;
arr[i].Average2 = arr[j].Average2;
arr[i].Average3 = arr[j].Average3;
arr[i].Average4 = arr[j].Average4;
}
int Student_SearchByName(char name[]) {
//通过姓名来检索学生
int i;
for (i = 0; i < num; i++) {
if (strcmp(students[i].Name, name) == 0) { //通过strcmp函数来对比学生姓名，找到返回在数组的位置
return i;
}
}
return -1; //未找到返回 -1
}
int Student_SearchByIndex(char id[]) { //通过学号来检索学生信息
int i;
for (i = 0; i < num; i++) {
if (strcmp(students[i].ID, id) == 0) { //通过strcmp函数来对比学生id，找到返回位置
return i;
}
}
return -1; //未找到返回 -1
}
void Student_DisplaySingle(int index) { //输出表头
printf("%10s%10s%8s%8s%10s%10s%10s%10s\n", "学号", "姓名", "语文", "数学", "英语",
"平均成绩""语文科目平均成绩""数学科目平均成绩""英语科目平均成绩");
printf("-------------------------------------------------------------\n");
printf("%10s%10s%8.2f%8.2f%8.2f%8.2f%10.2f%10.2f\n", students[index].ID, students[index].Name,
students[index].Mark1, students[index].Mark2, students[index].Mark3, students[index].Average1, students[index].Average2,
students[index].Average3, students[index].Average4);
}
void inputt() { //利用循环录入学生信息
while (1) {
printf("请输入学号:");
scanf("%s", &students[num].ID);
getchar();
printf("请输入姓名:");
scanf("%s", &students[num].Name);
getchar();
printf("请输入语文成绩:");
scanf("%f", &students[num].Mark1);
getchar();
printf("请输入数学成绩:");
scanf("%f", &students[num].Mark2);
getchar();
printf("请输入英语成绩:");
scanf("%f", &students[num].Mark3);
getchar();
students[num].Average1 = (students[num].Mark1 + students[num].Mark2 + students[num].Mark3) / 3;
if (Student_SearchByIndex(students[num].ID) == -1) {
num++; //移向下一个位置
} else {
printf("学号重复，输入数据无效 !!!\n");
}
printf("是否继续?(y/n)");
if (getchar() == 'n') {
break;
}
}
}
void display() { //打印已录入的学生信息
int a;
printf("%10s%10s%8s%8s%8s%8s%10s%10s\n", "学号", "姓名", "语文", "数学", "英语", "平均成绩");
printf("-------------------------------------------------------------\n");
for (a = 0; a < num; a++) {
printf("%10s%10s%8.2f%8.2f%8.2f%8.2f%10.2f%10.2f\n", students[a].ID, students[a].Name,
students[a].Mark1, students[a].Mark2, students[a].Mark3, students[a].Average1);
}
}
void search() { //查询学生信息
while (1) {
char name[20];
int index;
printf("请输入要查询的学生的姓名:");
scanf("%s", &name);
getchar();
index = Student_SearchByName(name); //调用搜查name函数，根据其返回值确定位置
if (index == -1) {
printf("学生不存在!\n");
} else {
printf("你要查询的学生信息为:\n");
Student_DisplaySingle(index);
}
printf("是否继续?(y/n)");
if (getchar() == 'n') {
break;
}
}
}
void sort() { //根据平均分排序
int i, j; //struct students tmp;
for (i = 0; i < num; i++) {
students[i].Average1 = (students[i].Mark1 + students[i].Mark2 + students[i].Mark3) / 3;
}
for (i = 0; i < num; i++) {
for (j = 1; j < num - i; j++) {
if (students[j - 1].Average1 < students[j].Average1) {
Copy(students, num, j - 1);
Copy(students, j - 1, j);
Copy(students, j, num);
//tmp=students[j-1];
//students[j-1]=students[j];
//students[j]=tmp; //冒泡排序
}
}
}
int a;
printf("%10s%10s%8s%8s%8s%10s\n", "学号", "姓名", "语文", "数学", "英语", "平均成绩");
printf("-------------------------------------------------------------\n");
for (a = 0; a < num; a++) {
printf("%10s%10s%8.2f%8.2f%8.2f%8.2f%10.2f%10.2f\n", students[a].ID, students[a].Name,
students[a].Mark1, students[a].Mark2, students[a].Mark3, students[a].Average1);
}
}
void SearchLow() { //搜索不及格的并输出
int a;
printf(" 语文不及格的有%10s%10s%8s\n", "学号", "姓名", "语文");
for (a = 0; a < num; a++) {
if (students[a].Mark1 < 60)
printf("%10s%10s%8.2f\n", students[a].Name, students[a].ID, students[a].Mark1); //从头搜索到尾，若小于60就输出
}
printf(" 数学不及格的有%10s%10s%8s\n", "学号", "姓名", "数学");
for (a = 0; a < num; a++) {
if (students[a].Mark2 < 60)
printf("%10s%10s%8.2f\n", students[a].Name, students[a].ID, students[a].Mark2);
}
printf(" 英语不及格的有%10s%10s%8s\n", "学号", "姓名", "英语");
for (a = 0; a < num; a++) {
if (students[a].Mark3 < 60)
printf("%10s%10s%8.2f\n", students[a].Name, students[a].ID, students[a].Mark3);
}
printf(" 计算机不及格的有%10s%10s%8s\n", "学号", "姓名", "计算机");
system("pause"); //这个好像没作用
}
void Save() {
FILE *fp = fopen("temp.txt", "w+");
fprintf(fp, "%d\n", num);
for (int i = 0 ; i < num ; i++) {
fprintf(fp, "%s %s %f %f %f %f %f %f\n", students[i].ID, students[i].Name, students[i].Mark1, students[i].Mark2,
students[i].Mark3, students[i].Average1);
}
fclose(fp);
}
void Load() {
FILE *fp = fopen("temp.txt", "r");
fscanf(fp, "%d", &num);
for (int i = 0 ; i < num ; i++) {
fscanf(fp, "%s %s %f %f %f %f %f %f\n", students[i].ID, students[i].Name, &students[i].Mark1, &students[i].Mark2,
&students[i].Mark3, &students[i].Average1);
}
fclose(fp);
}
int main() {
int i;
while (1) {
Load();
printf("\t\t\t\t\t-------- 学生成绩管理系统-------\n\n\n\n"); //菜单
printf("\t\t\t\t\t1. 增加学生记录\n\n");
printf("\t\t\t\t\t2. 修改学生记录\n\n");
printf("\t\t\t\t\t3. 删除学生记录\n\n");
printf("\t\t\t\t\t4. 插入学生记录\n\n");
printf("\t\t\t\t\t5. 显示所有记录\n\n");
printf("\t\t\t\t\t6. 查询学生记录\n\n");
printf("\t\t\t\t\t7. 按平均成绩排序\n\n");
printf("\t\t\t\t\t8. 输出各科目不及格学生\n\n");
printf("\t\t\t\t\t9. 输出各科目最高分\n\n");
printf("\t\t\t\t\t0. 退出\n\n\n");
printf("请选择(0-9):");
scanf("%d", &i);
switch (i) {
case 1:
inputt();
break;
case 2:
display();
break;
case 3:
search();
break;
case 4:
sort();
break;
case 5:
SearchLow();
break;
case 0:
exit(0);
default:
;
}
Save();
}
return 0;
}
