Bangla Number (Sourav Da)

//challenge
#include<stdio.h>
#include<string.h>


int main()
{
     int len,mod,i,j,k,loop,flag,flag7,flag5,flag2;
     char str[100];
     while(scanf(" %s",str) == 1)
     {
          len = strlen(str);
          j=0;
          while(str[j] == '0') //this loop is for eluminating leading 0's.
          {
               if(len == 1)//if the number is 0,then last digit will be kept.
               break;
               len--;
               j++;
          }

          loop=(len+6)/7;
          mod = len %7;

          if(mod == 0)
          mod = 7;
          flag=0;

          for(i=0; i<loop; i++)
          {
                    flag7=flag5=flag2=0;

                    if(i) //kuti will not be printed in first time.
                    {
                         printf(" kuti");
                         flag =1;
                    }

                    if(mod == 7) //such if is used to determine the starting point of the number
                    {
                         mod--;
                         if(str[j] != '0')
                         {
                              if(flag)
                              {
                                   putchar(' ');
                                   flag=0;
                              }
                              printf("%c",str[j]);
                              flag7 = 1;
                         }
                         j++;
                    }
                   if(mod == 6)
                   {
                        mod --;
                        if(str[j] != '0' ||  flag7) {
                             if(flag)
                              {
                                   putchar(' ');
                                   flag=0;
                              }

                        printf("%c lakh",str[j]);
                        j++;
                        flag =1;
                        }
                   }

                   if(mod == 5)
                    {
                         mod--;
                         if(str[j] != '0')
                         {
                              if(flag)
                              {
                                   putchar(' ');
                                   flag=0;
                              }
                              printf("%c",str[j]);
                              flag5 = 1;
                         }
                         j++;
                    }
                   if(mod == 4)
                   {
                        mod --;
                        if(str[j] != '0' ||  flag5) {
                             if(flag)
                              {
                                   putchar(' ');
                                   flag=0;
                              }
                        printf("%c hajar",str[j]);
                        }
                        j++;
                        flag =1;
                   }

                   if(mod == 3)
                   {
                        mod--;
                        if(str[j] != '0') {
                             if(flag)
                              {
                                   putchar(' ');
                                   flag=0;
                              }
                        printf("%c shata",str[j]);

                        flag =1;
                        }
                        j++;
                   }

                   if(mod == 2)
                   {
                        mod--;
                        if(str[j] != '0')
                        {
                             if(flag)
                              {
                                   putchar(' ');
                                   flag=0;
                              }
                              printf("%c",str[j]);
                              flag2=1;
                        }
                        j++;
                   }

                   if(mod == 1)
                   {
                        mod = 7;
                        if(flag2 ==1 || str[j] != '0' || len == 1)
                        {
                             if(flag)
                              {
                                   putchar(' ');
                                   flag=0;
                              }
                             printf("%c",str[j]);
                        }
                        j++;
                    }
                    if(i && loop==(i-1)) { //last koti will print.
                    printf(" kuti");
                    flag = 1;
                    }

          }
          putchar('\n');
     }
    return main();
}