Question

Write a c++ program that accept any positive no. and then display the sum of all the no. form 1 up to the no. imputed. (for loop)
sample run:
Enter a no: 5
The sum is: 15

Answer 1

#include<stdio.h>
#include<stdlib.h>

int main(){
// a : Required number, i : for the loop, sum : to calcule the sum
int a, i=1, sum =0;
// A little message to tell the user to enter a number
printf("Enter a number : ");
// Read the value
scanf("%d",&a);
// Test if the value is positive or negative, if negative show an error message!
if (a < 0) printf("You entered %d, the number must be positive\n", a);
// Else if positive do the work
else {
// calculate the sum by looping until " i <= a "
for (i; i<=a; i++) sum = sum + i;
// Print the result in the screen
printf("The sum is : %d\n", sum);
}
// Prevent the program to exit
system("pause");
}

Answer 2

You should notice please that the Comments must be in the same line because I used the // , Thank you.

ktobah.

Answer 3

use cout and cin instead of printf and scanf for displaying output and taking input , if u r prgrmng in c++

Answer 4

True Mr. maheen_khizar, but still printf and scanf work well, I tried them.
Thanks for your suggestion.

ktobah.

Answer 5

yes printf and scanf work well , bt question was asked 4 c++ , thats why i suggest cin , cout

Answer 6

Alright, yes.

Answer 7

:-)

Answer 8

:P

Answer 9

#include "stdafx.h"
#include <iostream>

using namespace std;

int x =1;
int num;
int sum;

int _tmain(int argc, _TCHAR* argv[])
{
cout<<"Enter a positive no.: ";
cin>> num;
cout<<endl;

if (num<0)
{
cout<<"You entered " <<num<< " Please enter a postive number.\n";
}
else
{
for ( int x =1; x<=num;x++)

{
sum += x;
}

cout<<"Answer: "<<sum<<endl;
}

system("pause");
return 0;
}

@ktobah thanks for replying. but, i cant understand your code. so made my own. is this correct?

Answer 10

Well, I tried your code and it has some error (not much), and this is a corrected version of your code :
//#include "stdafx.h" // I turned this as a comment because stdafx.h is
// a proprietary library that you are using.
#include <iostream>

using namespace std;
int x =1; // you can write int x=1, num, sum; it's the same.
int num;
int sum;

int main(int argc, char* argv[]){
cout<<"Enter a positive no.: ";
cin>> num;
cout<<endl;
if (num<0){
cout<<"You entered " <<num<< " Please enter a postive number.\n";
}else{
for ( int x =1; x<=num;x++){
sum += x;
}
cout<<"Answer: "<<sum<<endl;
}
system("pause");
return 0;
}

NB : Sorry for the late reply we had here a problem with electricity, so I can't use Internet.
Good luck;

ktobah.

Answer 11

hey. thanks for replying. can you tell me what are the errors on my code?

Answer 12

Look at this line that you wrote : int _tmain(int argc, _TCHAR* argv[])
"_tmain" should be "main" because it's the main function, all the time your should write it like that.
"_TCHAR*" should be "char*" because it's a predefined type like that.

You're welcome and Good luck.