title: extracting letters and numbers from a string
body: <p>I have some difficulties with an assigned homework and wondered if I could get some help..
  Anyway the task is: "You have to enter random letters and numbers from the keyboard. The string should be analised from the program, after that all numbers must be extracted and it also has to sum them up.
  e.g. Input: asd-12sdf45-56asdf100  Output:77</p>
  
  <pre><code>#include&lt;stdio.h&gt; 
  #include&lt;stdlib.h&gt; 
  #include&lt;ctype.h&gt; 
  #include&lt;string.h&gt; 
  
  int main() { 
      char stringText[50]; 
      char arraySaver[50]; 
  
      int i=0, j=0, k=0; 
  
      printf("Enter String: "); 
      scanf("%s", &amp;stringText); 
  
      for(i=0; i&lt;strlen(stringText); i++) { 
          if(isdigit(stringText[i])) { 
              arraySaver[j]=stringText[i]; 
              j++; 
          } 
      } 
  
      system("pause"); 
      return 0; 
  } 
  </code></pre>