title: implicit declaration of functions?
body: <p>I'm still learning C and I understand that to get rid of most implicit declaration warnings, you add the prototype header at the beginning. But I'm confused as to what you do when you have outside methods being used in your code. </p>
  
  <p>This is my code when I'm using the outside methods</p>
  
  <pre><code>    #include &lt;stdio.h&gt;
      #include &lt;string.h&gt;
      int main(void)
      {
        int arrayCapacity = 10;
        int maxCmdLength = 20;
  
        int A[arrayCapacity];
        int count = 0; /* how many ints stored in array A */
        char command[maxCmdLength + 1]; 
        int n;
  
        while (scanf("%s", command) != EOF)
        {
  
           if (strcmp(command, "insert") == 0)
           {  
               scanf("%d", &amp;n);                   
               insert (n, A, arrayCapacity, &amp;count);
               printArray(A, arrayCapacity, count);
           }
           else if (strcmp(command, "delete") == 0)
           {
  
               scanf("%d", &amp;n);
               delete(n,A,&amp;count);
               printArray(A, arrayCapacity, count);
  
          }       
          else
          {
               scanf("%d", &amp;n);
               printArray(A, arrayCapacity, count);
          }
       }
       return 0;
      }   
  </code></pre>
  
  <p>The methods <code>printArray</code>, insert, and delete are all in the form of: <code>printArray.o, insert.o, delete.o</code></p>
  
  <p>This is how I compiled my program: <code>gcc -Wall insert.o delete.o printArray.o q1.c</code>
  and I get these warnings: </p>
  
  <pre><code>q1.c: In function âmainâ:
  q1.c:20: warning: implicit declaration of function `insert'
  q1.c:21: warning: implicit declaration of function `printArray'
  q1.c:30: warning: implicit declaration of function `delete'
  </code></pre>
  
  <p>I've tried including this in headers but I get errors saying file or directory not found.</p>
  
  <p>Any help appreciated.</p>