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