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/***autor：旋尘*time:.4.20*/#include<stdio.h>#include<stdlib.h>#include<windows.h>#include<string.h>#define MAXSIZE 50typedef struct {char num[12];//学号之所以用char,是为了后面strcmp看输入是否重复，他的类型是charchar name[20];char sex[4];//性别int score[3];//三科成绩float avg;//平均分int sum;//总分}Student;int student_number=0;///全局变量，可随便在函数里面改变引用Student student[MAXSIZE];///全局变量，可随便在函数里面改变引用int Menu(){int check_number;do{system("cls"); /*运行前清屏,把选择清掉*/printf("\t************学生成绩管理系统*************\n"); printf("\t*| 1. 添加学生信息 *\n");printf("\t*| 2. 显示学生信息 *\n");printf("\t*| 3. 按学号排序 *\n");printf("\t*| 4. 按总成绩排序 *\n");printf("\t*| 5. 查找单个学生 *\n");printf("\t*| 6. 删除指定学生 *\n");printf("\t*| 7. 修改学生信息 *\n"); printf("\t*| 8. 查看各门课程的平均分 *\n");printf("\t*| 9. 查看不及格的学生的信息 *\n");printf("\t*| 10. 清空已保存数据 *\n");printf("\t*| 0. 保存退出*\n");printf("\t*****************************************\n");printf("请输入选择(0-10):");scanf("%d",&check_number); if(check_number<0||check_number>10){printf("错误选择");system("pause");}}while(check_number<0||check_number>10);return check_number;}添加学生信息void Input(){int i;char choice='y';char clear[10];//清空缓冲区char student_num[12];//暂存学号，为了识别学号是否重复do{i=0;printf("请输入学号\t: ");scanf("%s",student_num);while(strcmp(student[i].num,student_num)!=0&&i<student_number){i++;}if(i<student_number){printf("学号已存在，请重新输入\n");}else{/*memset(student[i].number,0,sizeof(student[i].number));//我觉得没必要存在*/strcpy(student[i].num,student_num);printf("学生姓名\t: ");scanf("%s",student[i].name);printf("学生性别\t: ");scanf("%s",student[i].sex); printf("c语言成绩\t: ");scanf("%d",&student[i].score[0]);printf("数据结构成绩\t: ");scanf("%d",&student[i].score[1]);printf("数据库成绩\t: ");scanf("%d",&student[student_number].score[2]);student[i].avg=(float)(student[i].score[0]+student[i].score[1]+student[i].score[2])/3;student[i].sum=student[i].score[0]+student[i].score[1]+student[i].score[2];gets(clear);printf("此学生信息录入完毕，是否继续?(Y/N) :");scanf("%c",&choice);student_number++;不要漏了gets(clear);///防止当打多字符是影响后面的整形输入比如前面输入yy系统剩一个y输入%d，导致系统卡死，或者输入到学号里面去}} while (choice=='Y'||choice=='y');}显示学生信息void Show(){int i;printf("---------------------------------------------------------------------------------------------------------------------\n");printf("学生学号\t学生姓名\t学生性别\tc语言成绩\t数据结构成绩\t数据库成绩\t平均成绩\t总成绩\n");printf("---------------------------------------------------------------------------------------------------------------------\n");for(i=0;i<student_number;i++){printf("%s\t\t%s\t%s\t\t%d\t\t%d\t\t%d\t\t%f\t%d\n",student[i].num,student[i].name,student[i].sex,student[i].score[0],student[i].score[1],student[i].score[2],student[i].avg,student[i].sum);}之所以 %s\t是因为名字在4-8个格加5个空格能够大于八，就能被\t凑成16个格与上面对齐}///根据学号排序,大的在前void SortByNum(){Student temp;int i,j;for(i=0;i<student_number;i++){for(j=0;j<student_number-i-1;j++){if(strcmp(student[j].num,student[j+1].num)>0){temp=student[j];student[j]=student[j+1];student[j+1]=temp;}}}Show();}//根据总成绩排序,da\\大的在前void SortBySum(){Student temp;int i,j;for(i=0;i<student_number;i++){for(j=0;j<student_number-i-1;j++){if(student[j].sum<student[j+1].sum){temp=student[j];student[j]=student[j+1];student[j+1]=temp;}}}Show();}/查找单个学生void Search(){int i=0;int choice;char testnum[12];start :printf("请输入学号 : ");scanf("%s",testnum);i=0;不然循环回来时，i就不为0了while(strcmp(testnum,student[i].num)!=0&&i<student_number){i++;}if(i<student_number){printf("------------------------------------------------------------------------------------\n");printf("学生学号\t学生姓名\t学生性别\tc语言成绩\t数据结构成绩\t数据库成绩\t平均成绩\t总成绩\n");printf("------------------------------------------------------------------------------------\n");printf("%s\t\t%s\t%s\t\t%d\t\t%d\t\t%d\t\t%f\t%d\n",student[i].num,student[i].name,student[i].sex,student[i].score[0],student[i].score[1],student[i].score[2],student[i].avg,student[i].sum);printf("若继续查找按1，退出按0 :");}else{printf("查无此人，若继续查找按1，退出按0 :");}scanf("%d",&choice);if(choice){goto start;}}/删除学生信息void Delete(){int i=0,j;int choice;char testnum[12];start :printf("请输入学号 : ");scanf("%s",testnum);while(strcmp(testnum,student[i].num)!=0&&i<student_number){i++;}if(i<student_number){for(j=i;j<student_number-1;j++){student[j]=student[j+1];}student_number--;//没有删除，只是减少输出，之后再覆盖掉他printf("删除成功，若继续查找按1，退出按0 :");}else{printf("查无此人，若继续查找按1，退出按0 :");}scanf("%d",&choice);if(choice){goto start;}}修改学生信息void Modify(){int i=0,j;int choice;char testnum[12];start :printf("请输入学号 : ");scanf("%s",testnum);while(strcmp(testnum,student[i].num)!=0&&i<student_number){i++;}if(i<student_number){printf("-----------------------------------------修改前的数据------------------------------------------------------------------\n");printf("学生学号\t学生姓名\t学生性别\tc语言成绩\t数据结构成绩\t数据库成绩\t平均成绩\t总成绩\n");printf("-----------------------------------------------------------------------------------------------------------------------\n");printf("%s\t\t%s\t%s\t\t%d\t\t%d\t\t%d\t\t%f\t%d\n",student[i].num,student[i].name,student[i].sex,student[i].score[0],student[i].score[1],student[i].score[2],student[i].avg,student[i].sum);printf("开始修改\n");printf("学生学号\t: ");scanf("%s",student[i].num);printf("学生姓名\t: ");scanf("%s",student[i].name);printf("学生性别\t: ");scanf("%s",student[i].sex); printf("c语言成绩\t: ");scanf("%d",&student[i].score[0]);printf("数据结构成绩\t: ");scanf("%d",&student[i].score[1]);printf("数据库成绩\t: ");scanf("%d",&student[i].score[2]);student[i].avg=(float)(student[i].score[0]+student[i].score[1]+student[i].score[2])/3;student[i].sum=student[i].score[0]+student[i].score[1]+student[i].score[2];printf("-----------------------------------------修改后的数据------------------------------------------------------------------\n");printf("学生学号\t学生姓名\t学生性别\tc语言成绩\t数据结构成绩\t数据库成绩\t平均成绩\t总成绩\n");printf("-----------------------------------------------------------------------------------------------------------------------\n");printf("%s\t\t%s\t%s\t\t%d\t\t%d\t\t%d\t\t%f\t%d\n",student[i].num,student[i].name,student[i].sex,student[i].score[0],student[i].score[1],student[i].score[2],student[i].avg,student[i].sum);printf("修改成功，若继续查找按1，退出按0 :");}else{printf("查无此人，若继续查找按1，退出按0 :");}scanf("%d",&choice);if(choice){goto start;}}查看各门课程平均分void Show_avg(){int temp0=0,temp1=0,temp2=0;float a,b,c;int i;for(i=0;i<student_number;i++){temp0=temp0+student[i].score[0];temp1=temp1+student[i].score[1];temp2=temp2+student[i].score[2];}a=(float)(temp0/student_number);b=(float)(temp1/student_number);c=(float)(temp2/student_number);printf("c语言成绩平均分是%-.2f\n数据结构成绩平均分是%-.2f\n数据库成绩平均分是%-.2f\n",a,b,c);}///查看不及格的学生信息void Show_Max_And_Min(){int i,j=0,max,min;int keep_score[MAXSIZE];for(i=0;i<student_number;i++){if(student[i].score[0]<60||student[i].score[1]<60||student[i].score[2]<60){keep_score[j]=i;j++;}}j--;//因为退出循环的时候j又加了1，但这时keep_score[j]里面是空的,会引起异常printf("------------------------------------------------------------------------------------\n");printf("学生学号\t学生姓名\t学生性别\tc语言成绩\t数据结构成绩\t数据库成绩\t平均成绩\t总成绩\n");printf("------------------------------------------------------------------------------------\n");for(i=0;i<=j;i++){printf("%s\t\t%s\t%s\t\t%d\t\t%d\t\t%d\t\t%f\t%d\n",student[keep_score[i]].num,student[keep_score[i]].name,student[keep_score[i]].sex,student[keep_score[i]].score[0],student[keep_score[i]].score[1],student[keep_score[i]].score[2],student[keep_score[i]].avg,student[keep_score[i]].sum);}}void AddFromText(){FILE *fp;int i=0;if((fp=fopen("D:\\student.txt","r"))==NULL)fp=fopen("D:\\student.txt","w")要加括号才能与NULL比较{printf("打开文件失败，无读取数据");Sleep(1000);}else{fscanf(fp,"%d",&student_number); while(i<student_number){fscanf(fp,"%s%s%s%d%d%d%f%d",student[i].num,student[i].name,student[i].sex,&student[i].score[0],&student[i].score[1],&student[i].score[2],&student[i].avg,&student[i].sum);i++;}}fclose(fp);}将数据保存void Write(){/*int i;*/int i=0;///错误，没有初始化FILE *fp;if((fp=fopen("D:\\student.txt","w"))==NULL)fp=fopen("D:\\student.txt","w")要加括号才能与NULL比较{printf("保存失败");system("pause");}else{fprintf(fp,"%d",student_number);注意格式，中间是"%d",不是%dwhile(i<student_number){fprintf(fp,"\t%s\t%s\t%s\t%d\t%d\t%d\t%f\t%d\n",student[i].num,student[i].name,student[i].sex,student[i].score[0],student[i].score[1],student[i].score[2],student[i].avg,student[i].sum);上一行fprintf student[i].score等不要&，不然就是输入地址fscanf输入单个变量才需要这样用i++;}fclose(fp);printf("保存成功,正在退出系统");Sleep(1000);exit(0);}}/清空数据void FreeAll(){FILE *fp;int choice;printf("请确认是否清除，保存的信息删除无法恢复,确认清除输入1,否则输入0返回系统 : ");scanf("%d",&choice);if(choice){if((fp=fopen("D:\\student.txt","w"))==NULL)fp=fopen("D:\\student.txt","w")要加括号才能与NULL比较{printf("清除失败");system("pause");}else{printf("清除成功\n");fclose(fp);}}}int main(){AddFromText();for(;;){switch(Menu()){case 1:Input();system("pause");continue;case 2:Show();system("pause");continue;case 3:SortByNum();system("pause");continue;case 4:SortBySum();system("pause");continue;case 5:Search();system("pause");continue;case 6:Delete();system("pause");continue;case 7:Modify();system("pause");continue;case 8:Show_avg();system("pause");continue;case 9:Show_Max_And_Min();system("pause");continue;case 10:FreeAll();system("pause");continue;case 0:Write();}}}
