Sum of palindromic numbers

• Problem Description

  
  A number is called palindromic if its decimal representation is a palindrome. You are given a range, described by a pair of integers L and R. Find the sum of all palindromic numbers lying in the range [L, R], inclusive of both the extrema.
  
  Input
  The first line of the input contains an integer T denoting the number of test cases. The description of T test cases follows.
  
  The first line of each test case contains a pair of space separated integers L and R denoting the range for which you are required to find the sum of the palindromic numbers.
  
  Output
  For each test case, output a single line containing the sum of all the palindromic numbers in the given range.
  
  Constraints
  1<=T<=100
  Subtask 1 (34 points) : 1<=L<=R<=103
  Subtask 2 (66 points) : 1<=L<=R<=105
  Explanation
  Example case 1. The palindromic numbers between 1 and 10 are all numbers except the number 10. Their sum is 45.

• Test Case 1

  
  Input (stdin)

  2
  
  1 10
  
  123 150
  
  

  Expected Output

  sum is 45
  
  sum is 272

• Test Case 2

  
  Input (stdin)

  5
  
  1 10
  
  12 30
  
  100 200
  
  50 60
  
  250 300
  
  

  Expected Output

  sum is 45
  
  sum is 22
  
  sum is 1460
  
  sum is 55
  
  sum is 1360

Solution

#define ull unsigned long long

#include <stdio.h>

#include <stdbool.h>

bool ispal(int n){

  int m=n,res=0;

  while(n){

    res*=10;

    res+=n%10;

    n/=10;

  }

  return res==m;

}

int main(){

  int t;

  scanf("%d",&t);

  while(t--){

    int i,min,max;

    ull res=0;

    scanf("%d%d",&min,&max);

    for(i=min;i<=max;i++){

      if(ispal(i)){

        res+=i;

      }

    }

    printf("sum is %lld\n",res);

  }

  return 0;

}