#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 sum(int i,int j,int s){ for(int i=1;i<=j;i++){ s+=i; } cout<<s<<endl; return 0; } int main(){ sum(1,10,0); sum(20,30,0); sum(35,45,0); return 0; }