why is my If condition not working? ( C language) - c

Question

I'm making a train scheduling program. In my If condition, I only want to accept 10 train ids between 100 and 200. My program is running on command prompt but my If condition is totally ignored. How should I fix this so that my program will accept ids between 100 and 200 and request the user to enter the train id again if it's not obeying the condition?
My Code:
#include <stdio.h>
#include <stdlib.h>
typedef struct {
int train_id;
int train_time;
} TrainDetails;
void enterID(TrainDetails array[10]);
int main()
{
TrainDetails array[10];
enterID(array);
return 0;
}
void enterID(TrainDetails array[10])
{
int count = 1;
int enter_Tid;
while(count < 11)
{
printf("Enter Train ID :\n");
scanf("%d",&enter_Tid);
if(enter_Tid>100 && enter_Tid<200)
{
array[count].train_id = enter_Tid;
}
count++;
}
}

Answer 1

you should implement a slightly different approach (it was posted on a different post. Not the same thing but a similar structure that you can use: how to use a while loop to keep asking for input until the input is correct (C)?).
These are basic control flow structures, so I suggest reading a good beginners book on the basics of programming.
int tid = -1;
while (true){
printf("input an integer value: ");
scanf("%d",&tid);
if (tid > 100 && tid < 200 ){
printf("successfully read an item");
break;
} else {
printf("Invalid tid. Retry.");
}
}
If you don't want to use the break statement you can use this kind of basic control flow:
do {
printf("input an integer value: ");
scanf("%d",&tid);
} while (tid < 100 || tid > 200);
These should be inside a bigger loop where you decide how many of these train IDs you need.

Answer 2

Your program does not produce any output besides the "Enter Train ID" prompts, so the only way I can imagine for you to have concluded that your if condition is being ignored is by counting the number of prompts emitted before the program terminates. Seeing only ten total even in the event that you enter an out-of-range train id, you assume that the if condition that you are using to validate the inputs has been ignored.
But that depends on an aspirational expectation of how your program will behave, not a reasonable expectation of the code you actually presented. Consider, what work is performed by the code inside the if statement's body? Only one thing: assigning the entered ID to a train. So if the user enters an invalid ID then that will not happen, but everything else in the loop body still will. In particular, count is incremented at the end of the loop regardless of whether the input was valid.
You would have had more of a clue about what is going on if you had provided more feedback to the user. It is very unfriendly to reject an input without giving any notice that you have done so or any way for the user to recognize it. At least two reasonable feedback mechanisms could be easily integrated:
Update the prompt to tell the user for which train an ID is being requested:
printf("Enter the ID for Train %d :\n", count);
Add an else block to your validation test that, when executed, prints a message explaining that the ID was rejected.
I would probably do both, but the latter is the one that would make it clear that your if condition itself is working as expected. The former would help you recognize that the loop requests an ID only once for each train, regardless of whether a valid one is provided. It stores only valid IDs, but it never prompts for a replacement ID for an invalid one.