Question

I tried to make a program that writes struct elements to binary file and then writes the unique elements from the first file to another binary file. I compiled it with gcc and it works very good, but with MinGW the program freezes when it tries to open and create the second file. Do you have any idea where is the problem?

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

typedef struct element{
    char name[80];
    int p;
}ELEM;

void clear_stdin()
{
    char str[255];
    fgets(str,255,stdin);
}

int create()
{
    FILE *f;
    int d=0;
    int c;
    int n=0;
    ELEM s;
    f=fopen("file.bin","wb");
    if(f==NULL)
    {
        printf("create(): Could not open file.bin for read\n");
        return;
    }
    do{
    printf("Add elements to file?:\n1 - yes\n2 - no\n");
    scanf("%d",&c);
    if (c==1)
    {
        printf("Name=");
        clear_stdin();
        fgets(s.name,80,stdin);
        printf("P=");
        scanf("%d",&s.p);
        fwrite(&s,sizeof(ELEM),1,f);
        n++;
    }
    else
        d=1;
    } while(d==0);
    fclose(f);
    return n;
}

void show(int n)
{
    FILE *f;
    ELEM s;
    int i=0;
    if(n==0)
        return;
    f=fopen("file.bin","rb");
    while(i<n)
    {
        fread(&s,sizeof(ELEM),1,f);
        puts(s.name);
        printf("\t%d\n",s.p);
        i++;
    }
    fclose(f);
}

int add(int n)
{
    FILE *f;
    int d=0;
    int c;
    ELEM s;
    f=fopen("file.bin","ab");
    if(f==NULL)
    {
        printf("add(): Could not open file.bin for append\n");
        return;
    }
    do{
    printf("Add elements to file?:\n1 - yes\n2 - no\n");
    scanf("%d",&c);
    if (c==1)
    {
        printf("Name=");
        clear_stdin();
        fgets(s.name,80,stdin);
        printf("P=");
        scanf("%d",&s.p);
        fwrite(&s,sizeof(ELEM),1,f);
        n++;
    }
    else
        d=1;
    } while(d==0);
    fclose(f);
    return n;
}


void func(int n)
{
    FILE *f,*g;
    ELEM v[20],w;
    int i=0,j,k,x=0,s,gn=0,test;
    f=fopen("file.bin","rb");
    g=fopen("aux.bin","wb");
    if((g==NULL)||(f==NULL))
    {
        if(g==NULL)
            printf("function() : Could not open aux.bin for write\n");
        if(f==NULL)
            printf("function() : Could not open file.bin for read\n");
        return;
    }
    i=0;
    while(i<n)
    {
        fread(&v[i],sizeof(ELEM),1,f);

        i++;
    }
    for(j=0;j<n;j++)
    {
        for(k=j+1;k<n;k++)
        {
            if(v[j].p==v[k].p)
                x=1;

        }
        if(x==0)
        {
            s=strcmp(v[j].name,v[k].name);
            if(s!=0)
            {
                fwrite(&v[j],sizeof(ELEM),1,g);
                fread(&w,sizeof(ELEM),1,g);

                gn++;
            }
        }
        x=0;
    }
    test=fclose(g);
    if(test!=0)
        printf("function() : failed to closed file g\n");
    test=fclose(f);
    if(test!=0)
        printf("function() : failed to closed file f\n");
    g=fopen("aux.bin","rb");
    if(g==NULL)
    {
        printf("function() : Could not open aux.bin for read\n");
        return;
    }
    if(gn==0)
        return;
    i=0;
    while(i<gn)
    {
        fread(&w,sizeof(ELEM),1,g);
        puts(w.name);
        printf("\t%d\n",w.p);
        i++;
    }
    fclose(g);
}

int main()
{
    int k=0,r,n;
    do{
        printf("1 - create file\n2 - add elements to file\n3 - show elements\n4 - put unique elements in another file\n5 - exit program\n");
        scanf("%d",&r);
        switch(r)
        {
            case 1 : n=create(); break;
            case 2 : n=add(n); break;
            case 3 : show(n); break;
            case 4 : func(n); break;
            case 5 : k=1; break;
            default : printf("Command unrecognized!\n");
        }
    } while(k==0);
    return 0;
}

EDIT:
function func() is the only problem.

EDIT: Yes I can run it under gdb.

EDIT:
sizeof(ELEM)=84 offsetof(ELEM,p)=80 in both cases.

Answer 1

Wow guys you will not guess this: aux.bin, actually anything aux.* is a reserved filename on Windows! That’s why it is taking forever! Take a look here so you dont accidentally choose another reserved filename:
windows file name specification (search the page for ‘aux’)