Read file .txt and save it to struct in c - c

Question

I want to ask about file processing and struct in C language, I get an assignment from my lecture, and am so really confused about string manipulation in C programming. Here is the task.
get data from mhs.txt
store in struct
sort by name ascending
Here is the mhs.txt
1701289436#ANDI#1982
1701317124#WILSON#1972
1701331734#CHRISTOPHER STANLEY#1963
1701331652#SHINVANNI THEODORE#1962
1701331141#MUHAMMAD IMDAAD ZAKARIA#1953
1701331564#MARCELLO GENESIS DRIET J.#1942
1701322282#ANANDA AULIA#1972
1701329175#LORIS TUJIBA SOEJONOPOETRO#1983
1701301422#DEWI JULITA#1993
1701332610#HARRY HUTALIANG#1982
first before # is NIM,
after first # is name
and the last after #, is year
and here is what i've done
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct student{
char nim[11];
char name[50];
int year;
}s[10];
int main(){
FILE *fp;
int c,i,n;
printf("Read mhs.txt...");
getchar();
fp = fopen("mhs.txt", "r");
c = getc(fp);
i = 0;
while(c!=EOF){
printf("%c", c);
c = getc(fp);
i++;
}
fclose(fp);
getchar();
return 0;
}
First thing, I could save data on struct, but in here I very confused to separate a string.
That's all I know about struct and file processing, is there anyone who can help me? I have traveled around the internet and could not find the correct results.
Sorry if there are duplicate questions, and sorry if my english is too bad.

Answer 1

This is pure C code, you should new three import function: strtok & qsort & fsan.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct student
{
char nim[11];
char name[50];
int year;
};
#define BUFFER_SIZE 100
struct student saveToStruct (char* str)
{
struct student res;
int flag = 0;
char *token = strtok(str, "#");
while( token != NULL )
{
if (0 == flag)
strcpy(res.nim, token);
else if (1 == flag)
strcpy(res.name, token);
else
res.year = atoi(token);
flag++;
token = strtok( NULL, "#" );
}
return res;
}
void print(struct student* arr, int size)
{
for (int i = 0; i < size; i++)
{
printf("%s, %s, %d\n", arr[i].nim, arr[i].name, arr[i].year);
}
}
int cmp(const void* l, const void* r)
{
return strcmp(((const student*)l)->name, ((const student*)r)->name);
}
int main()
{
struct student arr[10];
FILE* file = fopen("mhs.txt", "r");
if (!file)
return -1;
char buffer[BUFFER_SIZE];
int flag = 0;
while (fgets(buffer, BUFFER_SIZE, file))
{
arr[flag] = saveToStruct(buffer);
flag++;
}
print(arr, 10);
qsort(arr, 10, sizeof(struct student), cmp);
printf("After sort by name!\n");
print(arr, 10);
return 0;
}

Answer 2

Since you've tagged this as C++, I'd use C++:
#include <iostream>
#include <string>
#include <algorithm>
struct student {
std::string nim;
std::string name;
int year;
bool operator<(student const &other) {
return name < other.name;
}
friend std::istream &operator>>(std::istream &is, student &s) {
std::getline(is, s.nim, '#');
std::getline(is, s.name, '#');
return is >> s.year;
}
};
int main() {
std::ifstream in("mhs.txt");
std::vector<student> students{
std::istream_iterator<student>(in),
std::istream_iterator<student>()
};
std::sort(students.begin(), students.end());
}
If you want to accomplish roughly the same thing in C, it's probably easiest to do the reading with fscanf using a scanset conversion, like:
fscanf(infile, "%10[^#]#%49[^#]#%d", student.nim, student.name, &student.year);
The scanset conversion gives you something like a subset of regular expressions, so the %[^#] converts a string of characters up to (but not including) a #. In this case, I've limited the length of each to one less than the length you gave for the arrays in your struct definition to prevent buffer overruns.
Then you can do the sorting with qsort. You'll need to write a comparison function, and doing that correctly isn't always obvious though:
int cmp(void const *aa, void const *bb) {
student const *a = aa;
student const *b = bb;
return strcmp(a->name, b->name);
}

Answer 3

Here are some hints, not the full answer. Hope it could help you.
first you need to read the file line by line, instead of character by character. You need the function of fgets(). you may find the reference from www.cplusplus.com/reference/cstdio/fgets/
second you can use strtok() to seperate strings. here is an example.
char str[] = "now # is the time for all # good men to come to the # aid of their country";
char delims[] = "#";
char *result = NULL;
result = strtok( str, delims );
while( result != NULL ) {
printf( "result is \"%s\"\n", result );
result = strtok( NULL, delims );
}
and you may find the reference to strtok() from http://www.cplusplus.com/reference/cstring/strtok/
third, use qsort() to sort the structure array. you may find the reference of it from http://www.cplusplus.com/reference/cstdlib/qsort/. examples can also be found there.