How can I read numbers from an external text file in C?

Make sure to check the result of your scanf function to see if it's reading the input correctly. You can add error handling for cases where the input is not what you expect. Here’s an example code snippet:

```c
#include
int main() {
for (int n, result;;) {
result = scanf("%d", &n);
if (result == 1) {
if (n >= 1 && n <= 6) {
printf("Valid: %dn", n);
} else {
printf("Out of bounds: %dn", n);
}
} else {
if (result = 0 && c != 'n';);
}
}
}
```
This helps to ensure that your program can handle wrong inputs without getting stuck! You can check it out on platforms like godbolt.org for testing.

First off, how is your program set up to read from the input.txt file? Just checking because it’s important for it to know where to retrieve the data from! You might want to use a command like `gcc ex.c -o program.exe` followed by `Get-Content input.txt | ./program.exe` to run it properly and see if that helps. Let me know what you think!

Can you share what the content of your input.txt file looks like? It might help diagnose the issue if we can see the actual data your program is trying to read.