#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() #include<cstring> // strcpy()\strcat()\strcmp()\strlen()\memset() #include<cmath> //sqrt()\pow()\abs()\ceil()\floor()\max()\min() using namespace std; int a(int x,int y){ int sum=0; for(int i=x;i<=y;i++){ sum+=i; } return sum; } int main(){ cout<<a(1,10)<<endl; cout<<a(20,30)<<endl; cout<<a(35,45)<<endl; return 0; }