Initialize array elements at run time

Question

I am new to C, and I am trying to initialize array elements at run time, according to user input (so if the user inputs 4, then array[0]=4).

I have the following code:

#include<stdio.h>
#define MAX 10
#define maxValue 100

int array[MAX];
int n;
int main(void){
   scanf("%d", n); //asks for array value
   if (n <= maxValue)
   {
      array[0] = n;
   }
   return 0;
}

The code compiles, but triggers an access violation. What's wrong?

Please try to find the flags that allow the compiler you use to warn you about such problems. With GCC, a sensible option to use is -Wall to catch a large variety of such errors. Other compilers will probably need other options. — Jonathan Leffler
– Jonathan Leffler, Commented Apr 1, 2015 at 23:30

DanielG · Accepted Answer · 2015-04-01 23:42:44Z

2

You should be passing &n to scanf.

scanf("%d", &n);

As Jonathan pointed out, this is easily caught by a compiler warning. For gcc you can use -Wall which will show you:

warning: format specifies type 'int *' but the argument has type
  'int' [-Wformat]
scanf("%d", n); //asks for array value
       ~~   ^

edited Apr 1, 2015 at 23:42

answered Apr 1, 2015 at 23:28

DanielG

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1 Comment

Pasha Shestakov Over a year ago

I totally forgot about the address of operator! Such a noob mistake. Code works now. Thanks for your help.

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