Question

5. Write a program that asks the user for a positive integer value. The program should use a loop to get the sum of all the integers from 1 up to the number entered. For example, if the user enters 50, the loop will find the sum of 1, 2, 3, 4, ... 50. Input Validation: Do not accept a negative starting number.
C++ coding answer

Answer 1

The code for the above problem is:-

#include<iostream>
#include<bits/stdc++.h>
using namespace std;
main(){
int num,sum=0; //variable for storing input and result
cout<<"Please enter a positive integer \n"; //prompting the user for input
cin>>num;
while(num<=0) //checking if the input is negative or zero
{
   cin.clear(); //clearing the input stream
   cout<<"Invalid input . Please enter a positive integer \n"; //prompting the user to check his input
   cin>>num;   
   if(num>=1) //if the number entered is positive then stop checking the number
   break;
}

for(int i=1;i<=num;i++)
{
   sum=sum+i; //calculating the sum upto that number

}
cout<<"The sum upto "<<num<<" is "<<sum; // Displaying Result
}

The Screenshot of the code is provided below for proper indentation and positioning of comments:-

i 2 4 5 6 | 7 8 9 //variable for storing input and result //prompting the user for input #include<iostream> #include<bits/stdc++.h> using namespace std; main(){ int num, sum=0; cout<<"Please enter a positive integer \n"; cin>>num; while(num<=8) { cin.clear(); cout<<"Invalid input. Please enter a positive integer \n"; cin>>num; if (num>=1) break; //checking if the input is negative or zero 10 //clearing the input stream //prompting the user to check his input //if the number entered is positive then stop checking the number 14 15 E 17 18 V for(int i=1;i<=num; i++) { sum=sumi; 19 // calculating the sum upto that number E } cout<<"The sum upto "<<num<<" is "<<sum; } 22 23 24 // Displaying Result

OUTPUT:-

Please enter a positive integer -5 Invalid input . Please enter a positive integer -4 Invalid input . Please enter a positive integer 12 The sum upto 12 is 78 Process exited after 9.897 seconds with return value o Press any key to continue ...