C Programming Help! I have to read a file that acts as a user input for my progr

Question

C Programming Help!

I have to read a file that acts as a user input for my program, andI'm trying to read a string of numbers from a file, and read them one by one in my program. For example, reading a string of 1's and 0's (101111111100). I want to get the string and parse each number into my program, but it's not doing that :(

Here is my program:

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

int main()
{
//Opens file
FILE *f;
int c;
f=fopen("test.txt","r");

while(input != 3){

printf("Error detection/correction: ");
printf("--------------------------- ");
printf("1) Enter parameters ");
printf("2) Check Hamming code ");
printf("3) Exit ");
printf("Enter selection: ");
fscanf(f, "%d", &input); printf("%d ", input);

if(input == 1){

printf(" Enter the maximum length: ");
fscanf(f, "%d", &length); printf("%d ", length);
ptr = (int*)malloc(length);
printf("Enter the parity (0=even, 1=odd): ");
fscanf(f, "%d", &parity); printf("%d ", parity);
}

if(input == 2){

printf("Enter the Hamming code: ");
//fscanf(f, "%s", str);
if( fscanf(f, "%s", ptr)!=NULL ) {
// puts(HammingOutput);
HammingCodeLength = strlen(ptr)-1;
printf(" ******Test: %c ", ptr);
}

}

printf(" *** Program Terminated Normally ");
free(ptr);
fclose(f);
return 0;
}

Test.txt file:

1
14
0
2
101111111100
3

Explanation / Answer

We can use sscanf to extract formated data from a string. (It works just like scanf,
but reading the data from a string instead of from standard input)

int GetNumber(const char *str) {
while (!(*str >= '0' && *str <= '9') && (*str != '-') && (*str != '+')) str++;
int number;
if (sscanf(str, "%d", &number) == 1) {
return number;
}
// No int found
return -1;
}
  

//this method will parse the string data into the program and extract the numbers from them.
  

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