Editing a .txt file?

[jigamuffin]

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:

Mary;May;12 Good Lane;02 6889 2456;[email protected];4567 7956 4562 4568;12/17;124;5559864582456;010134;
David;Bowie;In Space;09000000;[email protected];0000587945642134;10/99;458;795;010376;
Mr.;Tree;The Jungle; 12456;[email protected];46546464;65/12;656;5683655;010588;

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

#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);
    }

the ID is the last number of the line in the .txt file.
any hints or pointers are appreciated.

[Salem]

Editing a .txt file?