Hello everyone, I have a problem!. I am writing a code for a library program. i am at the stage of adding names and joined dates of members. The names are stored in an array and written to a file called members.txt. I would like to delete a member in the middle of the text file. After deletion i will load this new list of names back into the structure. Now the problem is When i delete a name in the MIDDLE. I dont want to leave empty spaces so i tried to use the "\r" to use the name below to overwrite the name i want to delete. It does not seem right to me. because when i print from the file the tab space does not work on the name directly below the deleted name. The relevant code is as follows : this is the delete function. Code: void delete_from_memfile(char members_name[50],struct members member[1000]) { // members_name = MEMBERS NAME ONLY. char members_det[58]; // this string reads a line from file (here DUMMY) int total_members,ctr,i=1; // ctr is the line number in file. char members_del[58]; // holds name and joined_date together from struct total_members = load_members(member); // load the structure from file FILE *members; members = fopen("members.txt","w"); // write to file the DELETED member if(members == NULL) { printf("\n\tWARNING : UNABLE to open members.txt\n"); return; } for(ctr=0;ctr<total_members;ctr++) { members_del[0] = '\0'; // clears the string if(!(strcmp(members_name,(member[ctr].name)))) // use ctr as line number to write { // ctr as member to be deleted. /*\r*/ strcpy((member[ctr].name),""); strcpy((member[ctr].joined_date),""); fprintf(members,"%s","\r"); continue; /* test printf("\n%s%s\n",(member[ctr].name),(member[ctr].joined_date));*/ } /* test else printf("\n%s%s\n",(member[ctr].name),members_name); */ strcat(members_del,(member[ctr].name)); // here do the string concatanate for ALL strings. strcat(members_del," "); strcat(members_del,(member[ctr].joined_date)); fprintf(members,"%s",members_del); // write line by line(ctr as line number) to file /* test printf("%s\n",members_del); */ members_del[0] = '\0'; // clears the string } /* test printf("%s\n",members_del); */ fclose(members); total_members = load_members(member); // load the structure from file return; } the load function loads the updated text file to the structure. Show function is to print from the text file. Code: void show(void) { char members_det[58]; // a line from file FILE *members; members = fopen("members.txt","r"); if(members == NULL) { printf("\n\tWARNING : UNABLE to open members.txt\n"); return; } printf("\n\n\n\t\tNAME JOINED-DATE\n"); while(fgets(members_det,58,members)) // load a line into members_det string { printf("\t\t%s",members_det); } printf("\n\n"); fclose(members); return; } The entire code is shown below Code: #include<stdio.h> #include<string.h> #include<stdlib.h> struct borrowed { char member_name[50]; // to access from borrowed.txt file char items_name[150]; char type; char due_date[8]; }; struct members { char name[50]; char joined_date[8]; struct borrowed borrowed_items[5]; }; int security(char username[10],char password[10]); // fucntion prototypes void store_in_memfile(char members_init[58]); // stores name and joined date to file void delete_from_memfile(char members_name[50],struct members member[1000]); // deletes the member int update_total_members(void); int load_members(struct members member[1000]); // ONLY loads NAME and JOINED DATE to structure members, RETURNS total number of members void show(void); // START of MAIN int main() { char username[10],password[10]; int op=1; char members_init[58],members_det[58]; // name and joined_date char members_name[50]; // name to DELETE int total_members; // takes the value of line counter struct members member[1000]; printf("\n\t\tCalvary Life Assembly Digital Library\n\n\n"); while(1) // security while loop { printf("Please enter your USERNAME and PASSWORD\n"); strcpy(username,"x"); // clear the u_n and p_w strcpy(password,"x"); scanf("%s%s",username,password); if(security(username,password)) { continue; } else { printf("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n"); // hide the p_w printf("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n"); printf("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n"); printf("\nSECURITY CLEARED!\n\n"); break; } } // security while loop printf("\n\t\tCalvary Life Assembly Digital Library\n\n\n\n"); while(1) { fflush(stdin); printf("\n\tPress 1 - ADD New MEMBER\n\n"); printf("\tPress 2 - DELETE a MEMBER\n\n"); printf("\tPress 3 - VIEW All members\n\n"); printf("\tPress ctrl c - EXIT\n\n\n"); printf("You Entered --> : "); scanf("%d",&op); if(op == 1) { // read from keyboard printf("\nEnter FULL NAME with _ for spaces AND(after a space) Today's date <dd/mm//yy>.\n"); fflush(stdin); fgets(members_init,58,stdin); fflush(stdin); store_in_memfile(members_init); // append to members.txt file } if(op == 2) { printf("\n\tWARNING : You are about to DELETE a member.\n"); printf("\nEnter the FULL NAME with _ for spaces between words.\n"); fflush(stdin); scanf("%s",members_name); delete_from_memfile(members_name,member); // delete a member, sending MEMBER NAME ONLY } if(op == 3) { show(); } if(op == 4) { } total_members = update_total_members(); // update total_membters after store or delete members, // printf("\n\ntotal members = %d",total_members); load_members(member); // load members NAME and JOINED DATE from file into structure /* test*/ } system("pause > null"); return 0; } // END OF MAIN int security(char username[10],char password[10]) // 0 is correct and 1 is wrong { if(!(strcmp(username,"1")) && !(strcmp(password,"1"))) return 0; else return 1; } void store_in_memfile(char members_init[58]) { FILE *members; members = fopen("members.txt","a"); if(members == NULL) { printf("\n\tWARNING : UNABLE to open members.txt\n"); return; } if(members_init[0] != '\n') // capture the ENTER KEY and prevent it written to file. { fprintf(members,"%s",members_init); // add the new member } fclose(members); return; } int update_total_members(void) { FILE *members; int line_no=0; char members_det[58]; members = fopen("members.txt","r"); if(members == NULL) { printf("\n\tWARNING : UNABLE to open members.txt\n"); return 0; } while(fgets(members_det,58,members)) // update total_members { line_no = line_no + 1; } fclose(members); return line_no; // update total_members } void delete_from_memfile(char members_name[50],struct members member[1000]) { // members_name = MEMBERS NAME ONLY. char members_det[58]; // this string reads a line from file (here DUMMY) int total_members,ctr,i=1; // ctr is the line number in file. char members_del[58]; // holds name and joined_date together from struct total_members = load_members(member); // load the structure from file FILE *members; members = fopen("members.txt","w"); // write to file the DELETED member if(members == NULL) { printf("\n\tWARNING : UNABLE to open members.txt\n"); return; } for(ctr=0;ctr<total_members;ctr++) { members_del[0] = '\0'; // clears the string if(!(strcmp(members_name,(member[ctr].name)))) // use ctr as line number to write { // ctr as member to be deleted. /*\r*/ strcpy((member[ctr].name),""); strcpy((member[ctr].joined_date),""); fprintf(members,"%s","\r"); continue; /* test printf("\n%s%s\n",(member[ctr].name),(member[ctr].joined_date));*/ } /* test else printf("\n%s%s\n",(member[ctr].name),members_name); */ strcat(members_del,(member[ctr].name)); // here do the string concatanate for ALL strings. strcat(members_del," "); strcat(members_del,(member[ctr].joined_date)); fprintf(members,"%s",members_del); // write line by line(ctr as line number) to file /* test printf("%s\n",members_del); */ members_del[0] = '\0'; // clears the string } /* test printf("%s\n",members_del); */ fclose(members); total_members = load_members(member); // load the structure from file return; } int load_members(struct members member[1000]) // loads ONLY NAME and JOINED DATE to structure { FILE *members; char members_det[58]; // a line from file char *temp_name,*temp_joined_date; // strings to hold PARSE tokens int i=0; // struct counter members = fopen("members.txt","r"); if(members == NULL) { printf("\n\tWARNING : UNABLE to open members.txt\n"); return 0; } while(fgets(members_det,58,members)) // load a line into members_det string { temp_name = strtok(members_det," "); // parse the string members_det into tokens, first token is from 1st char to " ". temp_joined_date = strtok(NULL,""); // second token(string) is from char after " " to end of word/line. if(temp_joined_date == NULL) // precaution against blank lines in file. continue; strcpy((member[i].name),temp_name); strcpy((member[i].joined_date),temp_joined_date); i++; } // printf("\n%s %s\n",(member[9].name),(member[9].joined_date)); fclose(members); return i; } void show(void) { char members_det[58]; // a line from file FILE *members; members = fopen("members.txt","r"); if(members == NULL) { printf("\n\tWARNING : UNABLE to open members.txt\n"); return; } printf("\n\n\n\t\tNAME JOINED-DATE\n"); while(fgets(members_det,58,members)) // load a line into members_det string { printf("\t\t%s",members_det); } printf("\n\n"); fclose(members); return; }
Different OS sees new line differently. /n: Line Feed /r: Carriage return Windows: Sees new line as the combination CRLF. Carriage return and line feed. /r/n Unix: Sees new line as single line feed. /n Mac os: It knows only /r Hope this helps.
