Holy moly!!!

Hey folks,

I am completely new to C programming(just started taking it in a class at school).. I have a question.

I am making an if/else statement.

Code:

---

if (column_number<5&&column_number>0)
                {
                        printf("The average of column %i is: %.3le", column_number,average);
                }
        else
                {
                        printf("Invalid column number");
                }

---

So basically, if the number isnt 1 through 4, then it prints the "invalid column". But if I type in 2.4 or 3.5 it doesnt go to the invalid column statement. What signs can I use to make only 1,2,3 and 4 work ????

Thanks.. I have a feeling ill be on this forum a lot...

P.S.. i know my format (neatness) needs work

Cast the float/double to an int?

If you declared column_number as a int and then you are reading the user input with something like scanf("%d", &column_number); what will happen basically if the user enter something like 2.4, is that scanf will read and store the value 2 in column_number. This is how works scanf for integer, it reads the keyboard buffer for numeric character until it read a non-numeric character (approximately).

There would be different way to do so if the user enter something like 2.4. Like reading the user input in a buffer with fgets, than reading the buffer for an int with sscanf and reading again the buffer with sscanf for a float, then casting the int value to the float and checking if the comparaison is true; in that case, you could assume that the user enter a "real" integer.

I think that would work (but i have not tested).

(Edit: i just tested it and it does work. Here's my test program heh)

Code:

---

#include <stdio.h>
#define TAILLE 50

int main()
{
        char chaine[TAILLE];
        int i;
        int entier;
        float flottant;

        printf("Enter a number: ");
        fgets(chaine, TAILLE, stdin);

        i = sscanf(chaine, "%d", &entier);
        if (i != 0)
        {
                sscanf(chaine, "%f", &flottant);
                if ((float) entier == flottant)
                {
                        printf("Integer number.\n");
                }

                else
                {
                        printf("Decimal number.\n");
                }
        }
       
        else
        {
                printf("That's not even a number, moron.\n");
        }

        getchar();

        return 0;
}

---

cant find "fgets" in my textbook... what is that?? I will show you all the code that I have written...

Code:

---

#include "utils.h"
        #include  <stdio.h>


        #define filename "data.txt"

        int main ()
{

                int column_number;
                double average;


                FILE *f;
                f=fopen("data.txt", "r");

                printf("Enter the column number: ");
                scanf("&#37;i", &column_number);


                average = column_average(f,column_number);

        if (column_number<5&&column_number>0)
                {
                        printf("The average of column %i is: %.3le", column_number,average);
                }
        else
                {
                        printf("Invalid column number");
                }



                return 0;


}

---

fgets

ahhh.. got it.. thanks folks... I'll be back.. haha. guarenteed