title: Please explain what this code is doing (someChar - 48)
body: <p>I'm going through some practice problems, and I saw this code:</p>
  
  <pre><code>#include &lt;stdio.h&gt;
  #include &lt;string.h&gt;
  
  int main(void) {
     char* s = "357";
     int sum = 0;
     int i = 0;
     for (i = 0; i &lt; strlen(s); i++) {
       sum += s[i] - 48;
     }
     printf("Sum is %d", sum);
  
     return 0;
  }
  </code></pre>
  
  <p>Can someone explain what the code does, especially the subtraction with 48 part?</p>