title: What's wrong with my code? What is argv[1]?
body: <p>I'm trying to ask the user to type in a string so I will print the length of the string.  My code is built succeeded. However, when I entered a word and pressed 'enter', the program keeps running.  I had to enter a second word, then the length of the first string displays.  I'm confused at argv[1].  Can someone give me some tips and hint on how to fix this? Thanks in advance for your time.</p>
  
  <p>Please note that I'm not allowed to use any string function. </p>
  
  <pre><code>   int main(int argc, char* argv[]){
  
      char* s=argv[1];
  
      char input[256];
      s = input;
      printf("Please enter a string: ");
      scanf("%s\n", s);
      int str_length = 0;
      while (s[str_length] != '\0')
      {
          str_length++;
          if (s[str_length] == '\0') break;
      }
  
      printf("%d\n", str_length);
  
  
      return 0;   
  }
  </code></pre>