Thread: segmentation fault when using gcc

when I try to run this program it gives me an error message saying "segmentation fault". Any insight would be greatly appreciated. It compiles with gcc just fine. But I did not get this error when I compiled and ran it with Dev-C++.

Code:

///////////////////////////////////////////////////////////////////////////////
//
// Name: Sean Todd
// Date: Feb 14, 2005
// Desc: this program asks a usr to enter an int and tells the usr if it 
//is between 5 and 10 and also checks to see if valid data was entered
//
//////////////////////////////////////////////////////////////////////////////

#include <stdio.h>
#include <ctype.h>

int main(void)
{

   char input;

   printf("\nName: Sean Todd");
   printf("\nPlease enter an integer: ");
   scanf("%c", input);

   if(!isalnum(input))
   {
      printf("\nNo Data Could Be Read");
   }
   else if(!isdigit(input))
   {
      printf("\nData Was NOT an Integer");
   }
   else if(input > 53 && input <=57)
   {
      printf("\nThe Number, %c is between 5 and 10", input);
   }
   else
   {
      printf("\nThe Number, %c, is NOT between 5 and 10", input);
   }

   printf("\n\n");

   return 0;
}//end of main

thanks in advance
-Sean

Hello,

According to a reference on scanf(), these arguments must be pointers: if you want to store the result of a scanf operation on a standard variable you should precede it with the reference operator, i.e. an ampersand sign (&)

Code:

scanf("%c", &input);

- Stack Overflow

> It compiles with gcc just fine.
gcc -W -Wall -ansi -pedantic -O2
Now that catches an awful lot of things which may be wrong with your code, including mistakes in printf and scanf calls.

Hello,

According to the gcc man pages there are many Warning Options, e.g., -w, -W, -Wall, -Werror, -pedantic, -pedantic-errors, etc...

I do know for a fact -pedantic-errors caught different errors than -pedantic did. That may mean each flag serves its own purpose.


- Stack Overflow

There's a list, it's been referenced here before, that lists what flags include the other flags. I'm sure if one were to search they could find it.

Quzah.