Update record file in file - c

Question

Please help me. This is my code so far. The delete record function is not working and can someone help the update record function with following conditions:
- Ask user to input player name.
- Ask user to input player score.
- Ask user to input player level.
- If the player name does not exist on the list, then show message “name of [player name] not found!”
Thanks a lot.
#include <stdio.h>
#include <string.h>
struct Player {
char name[50];
int score;
int level;
};
struct Player data[50];
FILE *ptr;
FILE *ptr2;
int fileSize()
{
int lSize;
int end;
ptr = fopen("text.txt", "r");
lSize = ftell (ptr);
fseek (ptr, 0, SEEK_END);
end = ftell (ptr);
fseek (ptr, lSize, SEEK_SET);
return end;
}
int getNoOfRecords()
{
return (fileSize()/(sizeof(struct Player)));
}
void deletePlayerRecord()
{
char name[50];
int counter=0, i=0;
ptr2 = fopen("text2.txt","a");
int records = getNoOfRecords();
ptr = fopen("text.txt","a+");
do {
printf("Input player name[1..10]: ");
scanf("%[^\n]s", name);
fflush(stdin);
} while (strlen(name)<1 || strlen(name)>10);
while(counter!=records)
{
fread(&data,sizeof(struct Player),1,ptr);
if(strcmp(data[i].name,name)==0)
{
}
else
{
fwrite(&data,sizeof(struct Player),1,ptr2);
}
counter++;
}
fclose(ptr);
fclose(ptr2);
remove("text.txt");
rename("text2.txt","text.txt");
printf("\n%s successfully deleted.\n\n", name);
printf("Press Enter to continue....\n\n");
getchar();
}
void updatePlayerRecord()
{
char name[50];
int counter=0, i=0;
int records = getNoOfRecords();
ptr = fopen("text.txt","a+");
do {
printf("Input player name[1..10]: ");
scanf("%[^\n]s", name);
fflush(stdin);
} while (strlen(name)<1 || strlen(name)>10);
if(counter!=records)
{
fread(&data,sizeof(struct Player),1,ptr);
if(strcmp(data[i].name,name)==0)
{
}
counter++;
}
printf("\nScore and Level successfully updated.\n\n");
printf("Press Enter to continue....\n\n");
getchar();
}
void addPlayerRecord(){
int i=0;
do {
printf("Input player name[1..10]: ");
scanf("%[^\n]s", data[i].name);
fflush(stdin);
} while (strlen(data[i].name)<1 || strlen(data[i].name)>10);
fflush(stdin);
getchar();
data[i].score=0;
data[i].level=0;
ptr = fopen("text.txt", "a");
printf("\n");
fprintf(ptr, "\r\n%s#%d#%d", data[i].name, data[i].score, data[i].level);
fclose(ptr);
printf("\nData successfully added.\n\n");
printf("Press Enter to continue....\n\n");
getchar();
}
void viewPlayerRecord(){
int i=0;
ptr = fopen("text.txt", "r");
printf("Player Name\t\t|Average Score\t|Number of Playing\n");
printf("=======================================================\n");
while(fscanf(ptr, "%[^#]#%d#%d\n", data[i].name, &data[i].score, &data[i].level)!=EOF)
{
printf("%s\t\t\t|%d\t\t\t\t|%d\n", data[i].name, data[i].score, data[i].level);
i++;
}
fclose(ptr);
}
int main() {
int choice;
do{
printf("Score Record Dota Player\n");
printf("========================\n");
printf("1. View Record\n");
printf("2. Update Player Record\n");
printf("3. Add New Player\n");
printf("4. Delete Player\n");
printf("5. Save and Exit\n\n");
do {
printf("Input your choice[1..5]: ");
scanf("%d", &choice);
fflush(stdin);
getchar();
} while (choice < 1 || choice > 5);
switch (choice) {
case 1:
viewPlayerRecord();
break;
case 2:
updatePlayerRecord();
break;
case 3:
addPlayerRecord();
break;
case 4:
deletePlayerRecord();
break;
}
} while(choice!=5);
return 0;
}

Answer 1

There are many issues with your code:
Every operation works on the database file. That may be a good design, but a more usual approach would be to load the database into memory on startup, i.e. to populate your data and then work on this. When exiting the program, you commit all changes to the database file. (Your option 5 is named "Save and exit", but is effectively a null operation. That name hints at the outlined approach.)
You should make up your mind whether your database is a binary file or a text file. You use fprintf and fscanf, which are used for text files, when you add and display records, but you use fwrite and fread, which are used for binary files, when you update and delete records. In my opinion, binary access is a bit easier, because you just have to store and retrieve chunks of a fixed size, namely sizeof(struct Player). Text files are more user-friendly, because they can be displayed and modified in a text editor, but they have to be parsed and require more advanced error handling.
Your fileSize() will only work with binary files, but at the moment you write only text files. It is usually better to use the return values of the file functions to determine whether reading or writig was successful.
When the database file doesn't exist, your view function will crash. Check for file existence and for the correct format.
At the moment, you use data only as scratch space. You osften access data[i], but i is zero throughout your code.
A corrected delete function that works is:
void deletePlayerRecord()
{
struct Player p;
char name[50];
int del = 0;
ptr2 = fopen("text2.txt", "w");
ptr = fopen("text.txt", "r");
do {
printf("Input player name[1..10]: ");
scanf("%[^\n]s", name);
fflush(stdin);
} while (strlen(name)<1 || strlen(name)>10);
while (fscanf(ptr, "%[^#]#%d#%d\n", p.name, &p.score, &p.level) == 3) {
if(strcmp(p.name, name) == 0) {
printf("\n%s successfully deleted.\n\n", name);
del++;
} else {
fprintf(ptr2, "%s#%d#%d\n", p.name, p.score, p.level);
}
}
fclose(ptr);
fclose(ptr2);
remove("text.txt");
rename("text2.txt", "text.txt");
printf("%d character(s) deleted\n\n", del);
}
This code still has many drawbacks:
The success of fopen is not checked.
The fscanf and fprintf formats have to be copied verbatim from the view and add record options. That's bad style. You should probably write readPlayer and writePlayer functions.
The same goes for the input code. Write front-end functions that do the error checking so that you don't have to repeat the whole code over and over again. This makes the code hard to read and also prone to errors.