Question

Write a non-void method named sum that is passed two int parameters when it is called. It then uses a for-loop to compute and return the value of the sum of all the numbers between the value of the first parameter and the second, inclusive. This method does not display anything.

Give an example of how this method would be called, to produce output

Answer 1

Answer

Editable code

//non-void method named sum, whose return type is int. It take two integer parameters

int sum(int a,int b)
{
//total is initialized with 0 and it will be used to store value of desired sum.
int total=0;
  
//for loop to compute sum
//i will start from a and it will iterate till b, because we need both number inclusive in sum.
for(int i=a;i<=b;i++)
{
// sum is being performed here
total=total+i;
/*
working of for loop
let us suppose a=1 and b=5
initially i=1, total=0 and i will iterate till b.
  
total=total + i
0 = 0 + 1 ---> total=1
1 = 1 + 2 ---> total=3
3 = 3 + 3 ---> total=6
6 = 6 + 4 ---> total=10
10 =10 + 5 ---> total=15
*/
}
//return statement to return value of total(contains desired sum)
return total;
}

Code

Working c++ code

Output

Editable code

//C++ program to find sum using for loop
#include <iostream>
using namespace std;
//non-void method named sum, whose return type is int. It take two integer parameters
int sum(int a,int b)
{
//total is initialized with 0 and it will be used to store value of desired sum.
int total=0;
//for loop to compute sum
//i will start from a and it will iterate till b, because we need both number inclusive in sum.
for(int i=a;i<=b;i++)
{
// sum is being performed here
total=total+i;
/*working of for loop
let us suppose a=1 and b=5
initially i=1, total=0 and i will iterate till b.
  
total=total + i
0 = 0 + 1 ---> total=1
1 = 1 + 2 ---> total=3
3 = 3 + 3 ---> total=6
6 = 6 + 4 ---> total=10
10 =10 + 5 ---> total=15
*/
}
//return statement to return value of total(contains desired sum)
return total;
}
int main()
{
//variables a and b will be entered by user
int a,b;
cout<<"Enter a : ";
cin>>a;
cout<<"\nEnter b : ";
cin>>b;
//sum will return answer i.e. an integer value , so we need to store that in some integer first.
/*calling of sum function*/
int tot_sum=sum(a,b);
//printing value of tot_sum
cout<<"\nsum = "<<tot_sum;
   return 0;
}