expected primary-expression before 'else'

veronicak5678 · #1 07-Sep-2007, 13:47

I am tyring to write a simple program to display distance traveled. here are my instructions:

Write a program that asks the user for the speed of a vehicle (In miles per hour) and how many hours it has traveled. It should then use a loop to display the distance the vehicle has traveled for each hour of that time period. Her is an example of the output

What is the speed of the vehicle in mph? 40
How many hours has it traveled? 3

Hour Distance Traveled
--------------------------------------------------
1 40
2 80
3 120

Input validation:
Do not accept any negative number for speed and do not accept any value
less than one for time traveled.

The output should be formatted and aligned according to the above.

Here is my code so far:

CPP / C++ / C Code:

#include <cstdio>
#include <iostream>
#include <cmath>
using namespace std;

int main ()
{
int speed, distance, time, a, b;
a=1;
b=a*speed;

cout << "Distance Program";                                         
cout << "\n\n\nWhat is the speed of the vehicle in mph?\n";         
cin >> speed;                                                       
cout << "\nHow many hours has it traveled?\n";       
cin >> time; 

if (time >1 && speed >0)
  
       cout << "\n\nHour                  Distance Traveled"; 
       cout << "\n--------------------------------------\n";
        
        while (a<= time)
                {
                  a++;
                  cout << "\n";
                  cout << a;                    
                  printf("                      ");
                  cout << b;
                  cout << "\n";
                  
                  }      
             return 0;

else   
    
      {
       cout << "\n\nYou have entered invalid data\n\n";
       system("pause");
       }
}

I keep getting the "expected primary-expression before 'else'" error and the "expected ";" before 'else'" error. Am I missing something very simple? Imay not know much about programming, but I thought this was straight-forward!

davekw7x · #2 07-Sep-2007, 15:54

Quote:

Originally Posted by veronicak5678

I keep getting the "expected primary-expression before 'else'" e!

So: what do you have before your "else'?

The compiler ignores indentation. The "if" thingie only works on one statement; the one that follows immediately. If you need more than one statement, then put them in a block (surround the block with{} braces, as you did with the "while" thingie and the "else" thingie)

I have reformatted part of your code with indentation consistent with your logic.
Here is what the compiler sees:

CPP / C++ / C Code:

    if (time > 1 && speed > 0)  // only applies to the next statement
        cout << "\n\nHour                  Distance Traveled";

    cout << "\n--------------------------------------\n";

    while (a <= time) 
    {
        a++;
        cout << "\n";
        cout << a;
        printf("                      ");
        cout << b;
        cout << "\n";
    }
    return 0;

    else
    {
        cout << "\n\nYou have entered invalid data\n\n";
        system("pause");
    }

.

Regards,

Dave

ktcm · #3 08-Sep-2007, 09:48

Yeah, I also think that everything between the if and the else statement should be enclosed in {} braces for them to be processed as a 'if' block. I also think that the logic for calculating distance travelled should be within the while loop, as in this case, it is only calculating the distance travelled once.

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expected primary-expression before 'else'

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