Thread: Search and edit structure in binary file

Hello,

I am struggling with my code. I have a structure in a binary file and I need to make a function that searches a structure FIRM by a number and then proceeds to edit its previously typed profit.

This is the code in the main function:

Code:

case 4:        {
            fflush(stdin);
            printf("\nUpdate profit for firm with ID number:\n");
            gets(searchM);
            printf("\nNew profit:\n");
            scanf("%d", &newprofit);
            if (updateprofit(binary, filename, searchM, newprofit))
                printf("Update done!\n");
            else
                printf("Not updated!\n");
            system("pause");
            break;
        }

This is the header:

Code:

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


struct firm
{
    char idn[13];
    char name[40];
    char date[10];
    int profit;
    
};
typedef struct firm FIRM;


FILE *writeFile(char *fname);
void enter(FIRM **ps);
int readFile(FILE *fp, char *fname);
void display(FIRM *ps);
FILE *addInfo(char *fname);
int updateprofit(FILE *fp, char *fname, char *searchM, int newprofit);

And this is the function itself that gives and error and breaks the whole program.

Code:

int updateprofit(FILE *fp, char *fname, char *searchM, int newprofit){
    FIRM s;
    fp = fopen(fname, "r+b");
    if (!fp)
        return 0;
    while (fread(&s, sizeof(FIRM), 1, fp) == 1)
    {
        if (strcmp(s.profit, searchM) == 0)
        {
            s.profit = newprofit;
            fseek(fp, ftell(fp) - sizeof(FIRM), SEEK_SET);
            fwrite(&s, sizeof(FIRM), 1, fp);
            fclose(fp);
            return 1;
        }
    }
    fclose(fp);
    return (0);
}

Thanks in advance!

After I hit enter on new profit this happens.

I get exactly 0 warnings

Originally Posted by ghost00359

I get exactly 0 warnings

Then you need to increase the warning level of your compiler.
I assume you understand what the problem is as Salem showed you.