Thread: Editing a .txt file?

Hello. I want to edit a .txt file and I have no idea of how to do it - this is what I have come up with so far. With the .txt file reading this:

PHP Code:

Mary;May;12 Good Lane;02 6889 2456;maryblossom@yahoo.com;4567 7956 4562 4568;12/17;124;5559864582456;010134;David;Bowie;In Space;09000000;bowie@space.com;0000587945642134;10/99;458;795;010376;Mr.;Tree;The Jungle; 12456;tree@jungle.com;46546464;65/12;656;5683655;010588; 


When I run it, it prompts me to enter the new name but nothing happens.

Code:

#include <stdio.h>#include <string.h>
#include <stdlib.h>


typedef struct{
        char fname[32];
        char lname[32];
        char address [64];
        char phone [16];
        char email [64];
        char credit_num[32];
        char credit_expiry[16];
        char credit_bsb[4];
        char licence_num[32];
        int ID;
        }customer;


int main(){
    
    customer custData[128];
    int ch;
    char surname[32];
    char fname[32];
    FILE *cust;
    char address[64];
    char num[16];
    char mail[64];
    char crednum[32];
    char expiry[16];
    char bsb[4];
    char licnum[32];
    char line[18];
    char *item;
    int i = 0;
    int reccount = 0;
    int ID;
    int a;
    char newName[28];
int no;
    
    cust = fopen("customer.txt", "r");
    while(fgets(line,126,cust))
		{
			
			//for copying strings
			item = strtok(line, ";");
			
            strcpy(custData[reccount].fname, item);
			item = strtok(NULL, ";");
			
            strcpy(custData[reccount].lname, item);
			item = strtok(NULL, ";");
			
            strcpy(custData[reccount].address, item);
			item = strtok(NULL, ";");
			
            strcpy(custData[reccount].phone, item);
            item = strtok(NULL, ";");
		
        	strcpy(custData[reccount].email, item);
			item = strtok(NULL, ";");
			
            strcpy(custData[reccount].credit_num, item);
			item = strtok(NULL, ";");
			
            strcpy(custData[reccount].credit_expiry, item);
			item = strtok(NULL, ";");
			
            strcpy(custData[reccount].credit_bsb, item);
            item = strtok(NULL, ";");
			
            strcpy(custData[reccount].licence_num, item);
			item = strtok(NULL, ";");
		    
            custData[reccount].ID = atoi(item);
			
			reccount++;
			
   }
    fclose(cust);
    
    cust = fopen("customer.txt", "a");
    
    printf("1 - Find with customer ID");
    printf("\n2 - Find with customer name");
    scanf("%d", &ch); 
    switch(ch){
               case 1:
                    printf("Enter customer ID>");
                    scanf("%d", &ID);
               for(i=0;i<126;i++){
                        if(ID == custData[i].ID){
                              
                              printf("\n1 - Change first name\n2 - Change surname\n3 - Change address\n4 - Change phone\n5 - Change phone\n6 - Change credit card number\n7 - Change credit card expiry\n8 - Change credit card BSB\n9 - Change licence number\n");
			scanf("%d", &no);
                             
                               if(no==1){    
                                   printf("Enter new first name>");
                                   scanf("%s", custData[i].fname);
                                   fprintf(cust, "%s", fname);
                              }
				else if(no==2){
					
}
                              }
                        }


               /*
               case 2:
                    printf("Enter customer name>");
                    fgets(name, 62, stdin);
                    
               }
               */
               
    }
fclose(cust);
    }

any hints or pointers are appreciated.

Ypu need two functions

customer *readcustomers(char *filename, int *N)

int writecustomers(char *filename, customer *customers, int N)

Writing is easy. Just loop over the structure, calling printf() onthe fields.

Reading is harder. You will need to call malloc() and realloc() to grow the array dynamically. Often it makes things easier if you're allowed at all a "number of records" field at the start of the file. You need to fill in N to tell caller how many recors were in the file.

You test the functions agaisnt each other. call the write, then try to read the data you have just written, write it again, and examine the files to make sure they are the same.