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#include <stdio.h> #include <stdlib.h> typedef struct{ int id; char name[50];//产地名称 int yield; //产量(吨) }OrangeFarm; int main(){ OrangeFarm new_farm;//本次只需定义一个结构体变量用于追加 FILE *fp; //1。从控制台录入单条需要追加的数据 printf("---廉江红橙产地数据追加---\n"); printf("请输入新增产地信息(格式：ID名称产量):\n"); if(scanf("%d%s %d",&new_farm.id,new_farm.name,&new_farm.yield)!=3) { printf("输入格式错误。\n"); return 1; } //2。以追加模式("a")打开文件 //"a"代表append。如果文件不存在会创建；如果存在，指针直接指向文件末尾 fp=fopen("farms.txt","a"); //检查文件打开是否成功 if (fp == NULL){ printf("错误：无法打开文件进行追加!\n"); return 1; } // 3。使用fprintf 写入新数据 //务必保留末尾的\n，确保下一条追加的数据能另起一行 fprintf(fp,"%d %s %d\n",new_farm.id,new_farm.name,new_farm.yield); // 4。关闭文件 fclose(fp); printf("\n新记录已成功追加至farms.txt末尾。\n"); return 0; }2
#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 deleteId; char confirm; 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，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] %s", 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", &deleteId); int targetIndex = -1; for (int i = 0; i < count; i++) { if (farms[i].id == deleteId) { targetIndex = i; break; } } if (targetIndex == -1) { printf("错误：未找到 ID 为 %d 的记录。\n", deleteId); return 0; } printf("\n拟删除记录详情：\n"); printf("ID: %d | 名称: %s | 产量: %d 吨\n", farms[targetIndex].id, farms[targetIndex].name, farms[targetIndex].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 = targetIndex; 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\n", 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", deleteId); return 0; }3
#include <stdio.h> #include <stdlib.h> #include <string.h> typedef struct { int id; char name[50]; int yield; } OrangeFarm; int main(void) { OrangeFarm farms[100]; int count = 0; int targetId, choice, index; 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 %49s %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("\n--- 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", &targetId); index = -1; for (int i = 0; i < count; i++) { if (farms[i].id == targetId) { index = i; break; } } if (index == -1) { printf("未找到 ID 为 %d 的记录。\n", targetId); 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): "); 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，操作终止。\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", targetId); return 0; }4
#include <stdio.h> #include <stdlib.h> #include <string.h> typedef struct { int id; char name[50]; int yield; } OrangeFarm; int main(void) { FILE *fp; OrangeFarm temp; int threshold; int foundCount = 0; printf("----------- 廉江红橙产量筛选系统 -----------\n"); fp = fopen("farms.txt", "r"); if (fp == NULL) { printf("错误：无法打开数据文件 farms.txt，请确保文件已存在。\n"); return 1; } 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 %49s %d", &temp.id, temp.name, &temp.yield) == 3) { if (temp.yield > threshold) { printf("%-10d %-20s %-10d\n", temp.id, temp.name, temp.yield); foundCount++; } } printf("-------------------------------------------\n"); if (foundCount == 0) { printf("未找到产量超过 %d 吨的记录。\n", threshold); } else { printf("查询完毕，共找到 %d 条记录。\n", foundCount); } fclose(fp); return 0; }
