please help me Experts!

[maan]

i am having a problem about doing percentage in my first c++ program please help me and tell me the error in my proram i am putting the code below there is in the percentage something wrong when i execute my program in MS DOS it shows the percentage=0 please kindly tell me the problem thanks.

#include <iostream.h>

main()
{
int totalmarks , obtain1 , obtain2 , obtain3 , gpa , cgpa , percentage , totobtain;
obtain1 = 0;
obtain2 = 0;
obtain3 = 0;
cout << "Please enter the marks of subject 1...=";
cin >> obtain1;
cout << "Please enter the marks of subject 2...=";
cin >> obtain2;
cout << "Please enter the marks of subject 3...=";
cin >> obtain3;
cout << " Please enter total marks";
cin >> totalmarks;
totobtain= obtain1+obtain2+obtain3;
percentage = totobtain/totalmarks*100;
cout << "=====YOUR RESULT==== Obtain marks in given 3 subjects are =" <<totobtain <<"....Percentage is =" << percentage;


}

[maan]

what is the command/code/procedure to start the new line in c++

[yogurt]

first of all i dont no if ur getting an error but you need to use either
std::cout or std::cin
another choice is below the header put
using namspace std;
for the newline.
put std::endl or endl if u put namspace std;
here is your fixed code(i also changed header to a more modern version)

/*EDIT::::::::::::::::::::
i edited some stuff. i addend the endl's and 
i put a loop so you can choose if you want to try again. when you do try again system("CLS")
will clear the screen of previous stuff.And you are missing return 0;*/

#include <iostream>
using namespace std;
main()
{
char loop='y';     
  do
  {
  system("CLS");
  int totalmarks, gpa , cgpa , percentage , totobtain;
  int obtain1 = 0;
  int obtain2 = 0;
  int obtain3 = 0;
  
  cout << "Please enter the marks of subject 1...=";
  cin >> obtain1;
  cout << endl <<"Please enter the marks of subject 2...=";
  cin >> obtain2;
  cout << endl <<"Please enter the marks of subject 3...=";
  cin >> obtain3;
  cout << endl <<" Please enter total marks";
  cin >> totalmarks; 
  totobtain = obtain1+obtain2+obtain3;
  percentage = (totobtain/totalmarks)*100;
  cout << endl << "=====YOUR RESULT==== Obtain marks in given 3 subjects are =" 
       << totobtain <<"....Percentage is =" << percentage << endl;
  cout << "Would you like to try again? [y/n]: ";
  cin >> loop;
  }
   while(loop == 'y' || loop == 'Y');
return 0;
}

[maan]

sir,
i had put your code in dev c++ after executing it now also show the percentage=0. is there any problem in my Dev c++ ?

[z05DSL3A]

#include <iostream>

using namespace std;
int main()
{
    char loop='y';
    do
    {

        float totalmarks, gpa , cgpa , percentage , totobtain;
        float obtain1 = 0;
        float obtain2 = 0;
        float obtain3 = 0;
  
        cout << "Please enter the marks of subject 1 :=";
        cin >> obtain1;

        cout << endl <<"Please enter the marks of subject 2 :=";
        cin >> obtain2;

        cout << endl <<"Please enter the marks of subject 3 :=";
        cin >> obtain3;

        cout << endl <<" Please enter total marks :=";
        cin >> totalmarks;

        totobtain = obtain1 + obtain2 + obtain3;
        percentage = (totobtain/totalmarks) * 100.0;

        cout << endl << "=====YOUR RESULT==== Obtain marks in given 3 subjects are ="
             << totobtain <<"....Percentage is =" << percentage << endl;

        cout << "Would you like to try again? [y/n]: ";
        cin >> loop;

    }while(loop == 'y' || loop == 'Y');

    return 0;
}

[Faldrax]

Quick explanation on why your code was not working (see Gey Wolf's post above for corrected version).
The line

  percentage = (totobtain/totalmarks)*100;

was using integer arithmetic (as all varaibles were declared as int)

If we try toobtain = 120, totalmarks = 200
then toobtain/totalmarks = 120/200 = 0 !
0 * 100 = 0.
When you change these to Float, floating point arithmetic is used,
toobtain/totalmarks = 120.0/200.0 = 0.6
0.6 * 100.0 = 60.0.

[z05DSL3A]

Sorry, I did mean to come back and add an explanation of what I changed and why, work got in the way. ;0)