spoj http://www.spoj.com/problems/JULKA/ <pre><code> //explain below for loop what is actually being done in this loop// for(i=k-1, j=a=f=0; i&gt;=0; i--) { b = (a*10 + temp[i]-'0') / 2; //explain a = (a*10 + temp[i]-'0') % 2;//explain if(b) f = 1;//explain if(f) klaudia[j++] = b+'0';//explain } if(!j) j++;//explain klaudia[j] = 0;//explain for(i=len1-1, j=len2-1, k=c=0; i&gt;=0; i--, j--, k++) { a = total[i]-'0';//explain b = j&gt;=0? diff[j]-'0' : 0;//explain if(a &lt; b+c) { temp[k] = (10+a-b-c) + '0';//explain c = 1;//explain } else { temp[k] = a-b-c + '0';//explain c = 0;//explain } } temp[k] = 0;//explain </code></pre> <p>explain what is being done in both the for loop above why we are dividing and modulating by 2. what is the signifinace of adding 0 </p>