Thread: Problems with Reading and copying string from txt to console

There were some errors in the previous (untested) code I posted. In particular some incorrect variable names and extraneous ampersands before the string variables in the fscanf. Anyway, here's something that (barely) works for the format that you posted afterwards.

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
int main() {
    char search_id[100];
 
    printf("Enter ID: ");
    scanf("%s", search_id);
      
    FILE *fp = fopen("registration.txt", "r");
    if (!fp) {
        perror("Cannot open input file");
        exit(EXIT_FAILURE);
    }
 
    int cnt = 0;
    char line[1000], id[100], name[100], gender[100], age[100], birthday[100],
         food[100], start_d[100], end_d[100], course[100], fee[100];
 
    while (fgets(line, sizeof line, fp) != NULL)
    {
        if (!line[strspn(line, " \t\n")]) continue;  // blank or only whitespace
 
        if (sscanf(line, " ID:%99s", id) != 1) break;
        if (fscanf(fp, " Name:%99s Gender:%99s Age:%99s Birthday:%99s"
                       " Food:%99s Start date:%99s End date:%99s ",
                   name, gender, age, birthday, food, start_d, end_d) != 7) break;
 
        // course can contain spaces
        if (fgets(line, sizeof line, fp) == NULL) break;
        char *p = strchr(line, ':');
        if (!p) break;
        strcpy(course, p + strspn(p, ": \t\n")); // skip space, copy to course
        p = strchr(course, '\n'); // remove newline ...
        if (p) *p = '\0';         // ... if present
 
        if (fscanf(fp, " Fee:%99s", fee) != 1) break;
 
        if (strcmp(id, search_id) == 0)
        {
            printf("\n%s\n%s\n%s\n%s\n%s\n%s\n%s\n%s\n%s\n%s\n",
                   id, name, gender, age, birthday, food,
                   start_d, end_d, course, fee);
            ++cnt;
        }
    }
 
    fclose(fp);
  
    if (cnt == 0)
        printf("\nError: id %s not found.\n", search_id);
    else
        printf("\nFound %d record%s for id %s.\n",
               cnt, cnt > 1 ? "s" : "", search_id);
 
    return 0;
}

GOAL:

the goal is to try and read a txt file and print the content in the console
searching the id, it should display the the information for that specific id on the console

SOLUTION:

Code:

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

char chosen_ID[100], line_data[1024], record[2048];

void rem(char * s, char *what) {
    char *p = s; int l = strlen(p);
    while(p[l-1] == what[0]) p[--l] = 0;
    while(*p && (*p == what[0])) ++p, --l;
    memmove(s,p,l+1);
};

int readRecord(char *record_data,char *selector) {
    int read_record = 0;
    int skipper = 0;
    char *token = strtok(record_data, ":"); 
    while (token != NULL) {
        if (read_record == 1) {
            rem(token,":");
            if (sizeof(token)>1) printf("%s: ", token);
        };
        if (strcmp(token,selector) == 0) {
            read_record = 1;
        };
        token = strtok(NULL, ":"); 
        if ((skipper % 2) && (read_record == 1)) {
            printf("\n");
        };
        skipper++; 
    };
    return read_record;
};

void sweep(char *filename,char *getID) {
    FILE *fp = fopen(filename, "r");
    while(fgets(line_data, sizeof(line_data), fp) != NULL) {
        if ( (strcmp(line_data,"-\n") == 0) || (strcmp(line_data,"-") == 0) ) {
            int result = readRecord(record,getID);
            if (result == 1) break;
            memset(record,0,sizeof(record));
        } else {
            if (strcmp(line_data,"|\n") != 0) {
                rem(line_data,"\n");
                strcat(line_data,":");
                strcat(record,line_data);
            };
        };
    };
    fclose(fp);
};

int main(int args,char *argv[]) {
    printf("ID:"); 
    scanf("%s\0",chosen_ID);
    sweep("data.txt", chosen_ID);
    return 0;
};

quick n dirty

@Joe1709, beware of people like "Structure" who not only don't know C very well, but don't even know how to properly use a compiler. His "code" is riddled with errors. Just ignore him. Everyone else does.

Originally Posted by john.c

@Joe1709, His "code" is riddled with errors.

pffffft...

beware of people like "Structure"

what in tf ? lmao

fyi: i would suggest defining 100 since you used it a million times. also your brackets blow.

and since your rude... this is awful:

sizeof line

have you ever used a function before ?

sizeof is an operator, not a function

lol, i stand corrected.

POINT:

don't even know how to properly use a compiler.

Originally Posted by john.c

The code you've posted wouldn't even compile if it was part of a complete program (e.g., line 25).

Unfortunately, line 25 is insidiously syntactically correct. The code could be "correctly" formatted as:

Code:

if (same == 0)
{
    /* ... */
}
else
    (diff == 0);

{
    printf("ERROR\n");
}

Originally Posted by Structure

same should be either 1 or 0, true or false

It's just poor naming: same holds the return value of strcmp, which isn't boolean, but rather one of three possible values (or ranges thereof) to be compared with 0. It is more common to directly compare the return value of strcmp with 0 than to store it in a variable since if you do want to store something, it would be the result of the comparison, which means the result of comparing with 0.

Originally Posted by Structure

Code:

if (sizeof(token)>1) printf("%s: ", token);

You probably meant to call strlen instead of using sizeof here, and perhaps use >= or compare to 0.