for loop - C program to print numbers between 100 and 1000 which sum of digit is 20 -

i writing c program should display me numbers between 100 , 1000 sum of digit 20. tried code down here, displays 0 ouput when compile it, can me? tried moving if(ivsota==20) outside of while loop. using orwell dev c++ ide.

#include <stdio.h>  int main (void) {     int ivnos=0;     int iostanek=0;     int ivsota=1;     int istevec1=100;      for(istevec1=100; istevec1<1000; istevec1++)     {         while(istevec1>0)         {             iostanek=istevec1%100;             istevec1=istevec1/10;             ivsota=iostanek+ivsota;             if(ivsota==20)             {                 printf("%i\n", istevec1);             }         }     }     return(0); 

i hope better.

this should work you:

(changed variable names it's more readable)

#include <stdio.h>  int add_digits(int n) {     static int sum = 0;      if (n == 0)        return 0;      sum = n%10 + add_digits(n/10);     return sum;  }  int main() {      int start, end;     start = 100, end = 1000;      for(start = 100; start <= end; start++) {          if(add_digits(start) == 20)             printf("number: %d\n", start);     }      return 0;  } 

edit:

(your code fixed comments explanation)

#include <stdio.h>  int main() {      int ivnos=0;     int iostanek=0;     int ivsota=0;     int istevec1=100;     int temp;  //temp needed      for(istevec1=100; istevec1<=1000; istevec1++)     {          temp =istevec1; //assign number temp         ivsota=0;  //set sum every iteration 0         while(temp>0)         {             iostanek=temp%10;  //you need % 10 last digit of number             temp = temp / 10;  //'delete' last digit of number             ivsota+=iostanek;  //add digit sum          }           if(ivsota==20)  //you need check digits after sum calculated                 printf("number %d\n", istevec1);      }      return 0;  }