How to update struct text file line by line - c

Question

My code store all activities details in a file and I have problem accessing data in that file by searching using id. This is my add activities function and struct.
struct activities{
char id[5];
char actName[200];
char date[20];
char day[20];
}act;
//function to add volunteering activities
void addAct(){
FILE *fileAct;
//prompt user to enter activities details
printf("\n\t Planning Volunteering Activities");
printf("\n\t -----------------------------------");
printf("\n\t Program ID \t: ");
scanf(" %[^\n]%*c", &act.id);
printf("\t Name of Activity : ");
scanf(" %[^\n]%*c", &act.actName);
printf("\t Date \t\t: ");
scanf(" %[^\n]%*c", &act.date);
printf("\t Day \t\t: ");
scanf(" %[^\n]%*c", &act.day);
//create & write in file activity
fileAct = fopen("Activity", "a");
fprintf(fileAct, "\n\t %s \n", act.id);
fprintf(fileAct, "1. Name of Activity : %s \n", act.actName);
fprintf(fileAct, "2. Date : %s \n", act.date);
fprintf(fileAct, "3. Day : %s \n", act.day);
//close file activity
fclose(fileAct);
}
And this is my update function.
void updateAct(){
//variable declaration
char progID[5];
//open activity file
FILE *fp = fopen ("Activity", "r");
//prompt user to search activities to update
printf("\t Search by Program ID : ");
scanf(" %[^\n]%*c", &progID);
while( !feof(fp)){
fread (&act, sizeof(struct activities), 1, fp);
if (strcmp(progID, act.id) == 0)
printf("%s %s", act.id, act.actName);
}
fclose(fp);
}
In the update function above, I couldnt access the act.id in struct based on user search, instead, the program display the whole data in the file. How can fix this problem?

Answer 1

You provide pointers to char arrays, which technically is a pointer to a pointer. But scanf only needs pointers.
Remove the &'s of the scanf()-calls and add a maximum lengt specifier to your format arguments:
Change
scanf(" %[^\n]%*c", &progID);
to
scanf(" %4[^\n]%*c", progID);
for a 5 byte buffer.

Answer 2

void readLine(char* message, char* buffer, int buffer_size)
{
printf("\t%s: ", message);
fgets(buffer, buffer_size, stdin);
// fgets inserts '\n' at the end
// we are removing it
buffer[strlen(buffer) - 1] = '\0';
}
void addAct(){
FILE *fileAct;
struct activities newAct;
//prompt user to enter activities details
printf("\n\tPlanning Volunteering Activities");
printf("\n\t-----------------------------------\n");
readLine("Program ID", newAct.id, sizeof(newAct.id));
readLine("Name of Activity", newAct.actName, sizeof(newAct.actName));
readLine("Date", newAct.date, sizeof(newAct.date));
readLine("Day", newAct.day, sizeof(newAct.day));
//create & write in file activity
fileAct = fopen("Activity", "ab+");
if(NULL != fileAct) {
fwrite(&newAct, sizeof(struct activities), 1, fileAct);
//close file activity
fclose(fileAct);
}
}
void updateAct(){
//variable declaration
char progID[5];
struct activities readAct;
//open activity file
FILE *fp = fopen("Activity", "rb");
if(NULL != fp) {
//prompt user to search activities to update
printf("\tSearch by Program ID : ");
fgets(progID, sizeof(progID), stdin);
progID[strlen(progID) - 1] = '\0';
while(fread(&readAct, sizeof(struct activities), 1, fp) != 0){
if (strcmp(progID, readAct.id) == 0)
{
printf("%s %s\n", readAct.id, readAct.actName);
break;
}
}
fclose(fp);
}
}