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实验4 guochenghua

news 2026/3/26 23:37:57

T1增加数据

#include <stdio.h> #include <string.h> #include <stdlib.h> typedef struct{ int id; char name[50]; int yield; }OrangeFarm; int main(){ OrangeFarm farms[100]; int count = 0; int deleteld; char confirm; FILE *fp; fp = fopen("farms.txt","r"); if (fp == NULL){ printf("错误：无法打开farm.txt，请确保文件已存在。\n"); return 1; } while (fscanf(fp,"%d %s %d",&farms[count].id,farms[count].name,&farms[count].yield) == 3){ count++; } fclose(fp); if (count = 0){ printf("数据库为空，无数据可删除。\n"); return 0; } printf("\n---当前廉江红橙产地列表---\n"); for (int i = 0;i < count;i++){ printf("[%d] %-12s",farms[i].id,farms[i].name); if ((i + 1) % 3 ==0){ printf("\n"); } } printf("\n--------------\n"); printf("请输入要删除的产地ID："); scanf("%d",&deleteld); int targetlndex = -1; for (int i = 0;i < count;i++){ if (farms[i].id == deleteld){ targetlndex = i; break; } } if (targetlndex == -1){ printf("错误：未找到ID为%d的记录。\n",deleteld); return 0; } printf("\n拟删除记录详情：\n"); printf("ID：%d|名称：%s|产量：%d吨\n", farms[targetlndex].id,farms[targetlndex].name, farms[targetlndex].yield); printf("警告：此操作不可撤回！确定删除吗？（y/n)："); getchar(); scanf("%c",&confirm); if (confirm != 'y' && confirm != 'Y'){ printf("操作已安全取消。\n"); return 0; } for (int i = targetlndex;i < count - 1;i++){ farms[i] = farms[i + 1]; } count--; fp = fopen("farms.txt","w"); if (fp == NULL){ printf("系统错误：无法更新文件数据。\n"); return 1; } for (int i = 0;i < count;i++){ fprintf(fp,"%d %s %d",farms[i].id,farms[i].name,farms[i].yield); } fclose(fp); printf("成功：ID为%d的记录已从系统中彻底移除。\n",deleteld); return 0; }

T2删除信息

#include <stdio.h> #include <string.h> #include <stdlib.h> typedef struct{ int id; char name[50]; int yield; }OrangeFarm; int main(){ OrangeFarm farms[100]; int count = 0; int deleteld; char confirm; FILE *fp; fp = fopen("farms.txt","r"); if (fp == NULL){ printf("错误：无法打开farm.txt，请确保文件已存在。\n"); return 1; } while (fscanf(fp,"%d %s %d",&farms[count].id,farms[count].name,&farms[count].yield) == 3){ count++; } fclose(fp); if (count = 0){ printf("数据库为空，无数据可删除。\n"); return 0; } printf("\n---当前廉江红橙产地列表---\n"); for (int i = 0;i < count;i++){ printf("[%d] %-12s",farms[i].id,farms[i].name); if ((i + 1) % 3 ==0){ printf("\n"); } } printf("\n--------------\n"); printf("请输入要删除的产地ID："); scanf("%d",&deleteld); int targetlndex = -1; for (int i = 0;i < count;i++){ if (farms[i].id == deleteld){ targetlndex = i; break; } } if (targetlndex == -1){ printf("错误：未找到ID为%d的记录。\n",deleteld); return 0; } printf("\n拟删除记录详情：\n"); printf("ID：%d|名称：%s|产量：%d吨\n", farms[targetlndex].id,farms[targetlndex].name, farms[targetlndex].yield); printf("警告：此操作不可撤回！确定删除吗？（y/n)："); getchar(); scanf("%c",&confirm); if (confirm != 'y' && confirm != 'Y'){ printf("操作已安全取消。\n"); return 0; } for (int i = targetlndex;i < count - 1;i++){ farms[i] = farms[i + 1]; } count--; fp = fopen("farms.txt","w"); if (fp == NULL){ printf("系统错误：无法更新文件数据。\n"); return 1; } for (int i = 0;i < count;i++){ fprintf(fp,"%d %s %d",farms[i].id,farms[i].name,farms[i].yield); } fclose(fp); printf("成功：ID为%d的记录已从系统中彻底移除。\n",deleteld); return 0; }

T3修改信息

#include <stdio.h> #include <string.h> #include <stdlib.h> typedef struct{ int id; char name[50]; int yield; }OrangeFarm; int main(){ OrangeFarm farms[100]; int count = 0; int targetld,choice; FILE *fp; fp = fopen("farms.txt","r"); if (fp == NULL){ printf("错误：无法打开farms.txt,请确保文件已存在。\n"); return 1; } while (fscanf(fp,"%d %s %d",&farms[count].id,farms[count].name,&farms[count].yield) == 3){ count++; } fclose(fp); if (count == 0){ printf("数据库为空，请先添加数据。\n"); return 0; } printf("---当前系统内的产地ID列表---\n"); for (int i = 0;i < count;i++){ printf("[%d] %-12s",farms[i].id,farms[i].name); if ((i + 1) % 3 == 0){ printf("\n"); } } printf("\n-------------------------------\n"); printf("请输入您想要修改的产地ID："); scanf("%d",&targetld); int index = -1; for (int i = 0;i < count;i++){ if (farms[i].id == targetld){ index = i; break; } } if (index == -1){ printf("未找到ID为%d的记录。\n",targetld); return 0; } printf("\n已锁定产地：%s（产量：%d吨）\n",farms[index].name,farms[index].yield); printf("1.修改产地名称\n"); printf("2.修改预计产量\n"); printf("3.取消修改\n"); printf("请选择操作（1-3）\n"); scanf("%d",&choice); switch (choice){ case 1: printf("请输入新的名称："); scanf("%s",farms[index].name); break; case 2: printf("请输入新的产量（吨）："); scanf("%d",farms[index].yield); break; case 3: printf("操作已取消。\n"); return 0; default: printf("非法输入，操作中止。\n"); return 0; } fp = fopen("farms.txt","w"); if (fp == NULL){ printf("回写文件失败！\n"); return 1; } for (int i = 0;i <count;i++){ fprintf(fp,"%d %s %d\n",farms[i].id,farms[i].name,farms[i].yield); } fclose(fp); printf("ID为%d的记录已成功更新。\n",targetld); return 0; }

T4查询信息

#include <stdio.h> #include <stdlib.h> typedef struct{ int id; char name[50]; int yield; }OrangeFarm; int main(){ FILE *fp; OrangeFarm temp; int threshold; int foundCount = 0; fp = fopen("farms.txt","r"); if (fp == NULL){ printf("错误：无法打开farms.txt,请确保文件已存在。\n"); return 1; } printf("-----------廉江红橙产量筛选系统-----------\n"); printf("请输入产量阈值（吨)："); if (scanf("%d",&threshold) != 1){ printf("输入无效。\n"); fclose(fp); return 1; } printf("\n正在查询产量大于%d 吨的产地...\n",threshold); printf("-------------------------------------------\n"); printf("%-10s %-20s %-10s\n","ID","产地名称","预计产量（吨）"); printf("-------------------------------------------\n"); while (fscanf(fp,"%d %s %d",&temp.id,temp.name,&temp.yield) == 3){ if (temp.yield > threshold){ printf("%-10d %-20s %-10d\n",temp.id,temp.name,temp.yield); foundCount++; } } if (foundCount == 0){ printf("未找到产量超过%d的记录。\n",threshold); }else { printf("-------------------------------------------\n"); printf("查询完毕，共找到%d条记录。\n",foundCount); } fclose(fp); return 0; }

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