Sum of Numbers C

Question

I am supposed to 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   But for some reason it is not working  i am having trouble with my for loops but this is what i have down so far    include  lt iostream gt  using namespace std   int main         int positiveInteger      int startingNumber   1      int i   0       cout  lt  lt   Please input an integer up to 100    lt  lt  endl       cin  gt  gt  positiveInteger       for  int i 0  i  lt  positiveInteger  i                  i   startingNumber   1          cout  lt  lt  i             return 0       I am just at a loss right now why it isn t working properly

User · Answer

The loop is great  it s what s inside the loop that s wrong  You need a variable named sum  and at each step  add i 1 to sum  At the end of the loop  sum will have the right value  so print it

User · Answer

First  you have two variables of the same name i  This calls for confusion   Second  you should declare a variable called sum  which is initially zero  Then  in a loop  you should add to it the numbers from 1 upto and including positiveInteger  After that  you should output the sum

User · Answer

try this    include  lt iostream gt  using namespace std   int main         int positiveInteger      int startingNumber   1       cout  lt  lt   Please input an integer upto 100    lt  lt  endl       cin  gt  gt  positiveInteger       int result   0      for  int i startingNumber  i  lt   positiveInteger  i                  result    i          cout  lt  lt  result             cout  lt  lt  result       return 0

User · Answer

int result   0     for  int i 0  i  lt  positiveInteger  i                  result   startingNumber   1          cout  lt  lt  result

User · Answer

You are just updating the value of i in the loop  The value of i should also be added each time    It is never a good idea to update the value of i inside the for loop  The for loop index should only be used as a counter  In your case  changing the value of i inside the loop will cause all sorts of confusion   Create variable total that holds the sum of the numbers up to i    So   for  int i   0  i  lt  positiveInteger  i            total    i

User · Answer

I have the following formula that works without loops   I discovered it while trying to find a formula for factorials    include  lt iostream gt  using namespace std   int main         unsigned int positiveInteger      cout  lt  lt   Please input an integer up to 100    lt  lt  endl      cin  gt  gt  positiveInteger       cout  lt  lt   positiveInteger    positiveInteger   1     2      return 0

User · Answer

You can try   int sum   startingNumber   for  int i 0  i  lt  positiveInteger  i               sum    i    cout  lt  lt  sum    But much easier is to note that the sum 1 2     n   n  n 1    2  so you do not need a loop at all  just use the formula n  n 1  2

User · Answer

mystycs  you are using the variable i to control your loop  however you are editing the value of i within the loop   for  int i 0  i  lt  positiveInteger  i          i   startingNumber   1      cout  lt  lt  i      Try this instead   int sum   0   for  int i 0  i  lt  positiveInteger  i          sum   sum   i      cout  lt  lt  sum  lt  lt       lt  lt  i

[c++] Sum of Numbers C++

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