Need help distiguishing between Integer and double, Please Help!

[securelink]

I am taking a class on c at my university and I am on my second project and I have reached a problem. I have to write a program with a menu and 6 different math functions and I cant use the math library. That part I did fine, but my professor wants us to distiguish between Interger and double. So if the user enters 2 it will return 2, but if the user enters 2.0 it will return 2.0. I am about to rip my hair out trying to figure this part out. Please help! I am using jgrasp to compile.

Here is the closest i have got. It works when the user enters a double say 2.3 , it returns a 2.3 and if they enter a single iteger say 2 it returns 2 but it they enter 2.00 it returns 2. Help!

int main() {
input = 0;
input2 = 0;
scanf("%d.%d", &input, &input2);
if (input2 = 0){
     input = input2 + input
     prinf ("%d", input);
}
printf ("%d.%d", input, input2);
return 0;
}

[Salem]

Use fgets() to read the whole line into a buffer
Use strchr() to see if there is a '.' in the input
Use the appropriate sscanf() call to read an integer or a float, based on what you found

See the FAQ.

[securelink]

We have not been taught fgets(), or strchr() yet. I am not supposed to use the functions he has not gone over yet. Is there an alternative.

[Dante Shamest]

Read input as a string.
If there is a character ".", assume it's a float. Convert string to float.
Else assume it's an integer. Convert string to integer.

[dwks]

if (input2 = 0){

= is for assignment, == for comparison. That will always be false. You want to use ==.

[Micko]

Maybe i didn't understand correctly, but if you want to distinguish integer and double based on user input i think this code might help you:

#include <stdio.h>

int main (void)
{
    int x = 0;
    char buffer[10];
    int i;
    double xd = 0;
    scanf ( "%s", buffer );
    /* distinguish integers and doubles for further processing 
    and store them to appropriate variables */
    for (i = 0; buffer[i] != '.' && buffer[i] != '\0'; i++);
    if (buffer[i] == '\0')
    {
        sscanf (buffer, "%d", &x);
    }    
    else
    {
        sscanf (buffer, "%lf", &xd);
    }
    
    printf("%s", buffer); /*display exactly as entered*/
    return 0;
}

It will print as values as entered but it will distinguish integer input from double input.

[VirtualAce]

So you have to do a project yet use none of the functions that make it easier?

Ok, I get it.

Today's assignment is:
- Print your name 10000 times at random places in a window in MS Windows.
- You can't use the Win32 API, device contexts, or any other advanced text/graphic function.
- The window cannot be a console window.
- You are not allowed to use message loops.

[Salem]

Gotta love the "please fix this for me, but I'm not going to tell you which functions we're allowed to use" posts.
It's like teaching people to walk by first breaking their legs - muppet teachers!