[問題] C語言求助請問要如何刪除二進位檔案裡的資料內容?

看板C_and_CPP (C/C++)作者azure532 (當紅炸子機羅密歐)時間16年前 (2009/03/24 16:52)推噓1(1推 0噓 6→)

留言7則, 3人參與討論串1/1

這是小弟我寫的程式這個程式首先先讀取了store.txt 裡面的內容為A1 A2 A3 A4 再來good.bin為二進位檔案這個假設裡面有五筆資料我要刪除其中第三筆而最後兩筆依序往上補我該如何做呢?我想了很久還是不知道該如何去做麻煩各位先進前輩們指點迷津 #include <stdio.h> #include <string.h> typedef struct { int sn; char name[10]; char position[10]; }STORE; STORE goods; int main(void) { FILE *fp,*fptr; char *s=(char *)calloc(10,sizeof(char)); char **s1,*sss;//用來存store.txt檔案 int base;//選擇要做哪個動作 int idx=0;//用來當1.A1 2.B2的索引值 int i; int m;//用來做動態第一維元素的大小 int num;//用來選擇1=A1 2=A2的 int cmp;//比較sn是否相同 int numread; if((fp=fopen("store.txt","r"))!=NULL) { while((fgets(s,10,fp))!=NULL) { i++; } } else { printf("error"); } fclose(fp); m=i; s1=(char **)calloc(m,sizeof(char *)+(m*4,sizeof(char))); for(i=0,sss=(char *)(s1+m);i<m;i++,sss+=4) { s1[i]=sss; } while(1) { printf("**********\n"); printf("1.store in\n"); printf("2.search\n"); printf("3.display all\n"); printf("4.delete\n"); printf("5.exit\n"); printf("**********\n"); scanf("%d",&base); switch(base) { case 1: if((fp=fopen("goods.bin","a+b"))!=NULL) { printf("SN:"); fflush(stdin); scanf("%d",&goods.sn); printf("NAME:"); fflush(stdin); scanf("%s",goods.name); printf("position:("); fflush(stdin); if((fptr=fopen("store.txt","r"))!=NULL) { while((fgets(s,10,fptr))!=NULL) { strtok(s,"\r\n"); s1[idx]=s; printf("%d.%s:",idx,s1[idx]); idx++; if(idx==4) idx=0; s=(char *)calloc(10,sizeof(char)); } printf(")"); } else { puts("error"); } scanf("%d",&num); fflush(stdin); switch(num) { case 0: strcpy(goods.position,*(s1+0)); break; case 1: strcpy(goods.position,*(s1+1)); break; case 2: strcpy(goods.position,*(s1+2)); break; case 3: strcpy(goods.position,*(s1+3)); break; } printf("%d:%s:%s\n",goods.sn,goods.name,goods.position); fwrite(&goods,sizeof(STORE),1,fp); } else { puts("error"); } fclose(fp); fclose(fptr); break; case 2: if((fp=fopen("goods.bin","rb"))!=NULL) { printf("search SN:"); fflush(stdin); scanf("%d",&cmp); for(i=0;i<100;i++) { numread=fread(&goods,sizeof(STORE),1,fp); if(numread==0) { puts("not search"); break; } if(goods.sn==cmp) { printf("SN:%d\n",goods.sn); printf("Name:%s\n",goods.name); printf("location:%s\n",goods.position); break; } } } else { puts("error4"); } fclose(fp); break; case 3: if((fp=fopen("goods.bin","rb"))!=NULL) { for(i=0;i<100;i++) { numread=fread(&goods,sizeof(STORE),1,fp); if(numread==0) { break; } printf("SN:%d\t",goods.sn); printf("Name:%s\t",goods.name); printf("location:%s\n",goods.position); } } else { puts("error5"); } fclose(fp); break; case 4: if((fp=fopen("goods.bin","rb"))!=NULL) { } else { puts("error7"); } fclose(fp); break; case 5: exit(1); break; default: puts("not choose input again"); break; } } free(s); free(s1); return 0; } 抱歉程式很長~~請見諒 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 211.20.115.210