I am having a problem with the fscanf_s
function.
I made a code which it asks an user if they have a file for data input, and if they do it reads the data and get the values into the structure. Well, it doesn't work.
I tried to find an error by myself, but I failed, so I'm here looking for some help.
The first part where the user enters input and the programs creates a text file based on the input works, but as you can see the scanning part is not working. Any help will be great.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define size 10
char *filename = "file.txt";
char savefile[20];
struct Employee
{
char name[20];
float rate;
float hours;
}employee;
int main(void)
{
FILE *file;
FILE *output;
FILE *input;
int count = 0;
int yn;
int x = 0; int q = 0;
int o = 0; int k = 0;
int y = 0; int i = 0;
struct Employee guys[size];
printf("Do you have a file? 1. Yes 2. No\n");
scanf_s("%d", &yn);
if (yn == 2)
{
errno_t err = fopen_s(&file, filename, "w");
for (q = 0; q < size; q++)
{
puts("\ntype name: (type -1 to quit) \n");
scanf_s("%s", &guys[q].name, 20);
if (strcmp(guys[q].name, "-1") == 0) { break; }
puts("\ntype hourly rate: (type -1 to quit)\n");
scanf_s("%f", &guys[q].rate);
if (guys[q].rate == -1) { break; }
puts("\ntype hours worked: (type -1 to quit)\n");
scanf_s("%f", &guys[q].hours);
if (guys[q].hours == -1) { break; }
count++;
}
for (int q = 0; q < count; q++)
{
fprintf(file, "%s %f %f\n", guys[q].name,guys[q].rate, guys[q].hours);
}
fclose(file);
}
if (yn == 1)
{
errno_t err = fopen_s(&input, filename, "r");
if (err != 0)
{
printf("Unable to open up %s", filename);
return;
}
while (!feof(input))
{
fscanf_s(file, "%s" "%f" "%f", &guys[i].name,20,&guys[i].rate, &guys[i].hours);
i++;
}
fclose(input);
}
I used the file i created in the first part as the input for the second part. I also tested fscanf_s() without feof loop. Same problem still happens. the error keep popping says Exception thrown at 0x77506165 (ntdll.dll) in program05.exe: 0xC0000005: Access violation writing location 0xCCCCCCF0.
There are two problems in your read code which leads to crash.
You are passing closed file pointer to fscanf_s
function.
fclose(file);
You are passing invalid address 20
to fscanf_s function.
fscanf_s(file, "%s" "%f" "%f", &guys[i].name,20,&guys[i].rate, &guys[i].hours);
should be changed to
fscanf_s(input, "%s" "%f" "%f", &guys[i].name,&guys[i].rate, &guys[i].hours);
I would like to suggest you to not use
while (!feof(input))
Instead go with the below approach.
while (fscanf_s(input, "%s %f %f", &guys[i].name,&guys[i].rate, &guys[i].hours) == 3)
{
i++;
}
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