Thread: Hints to write a program

[QUOTE=Bnchs400]Actually, today my professor gave us a new assignment to do the same thing, this time using a single for loop in a function.

When the program is run, I have to enter two numbers and only the second number gets the "*" output. Does anyone have a suggestion on how to fix this?

Code:

#include <iostream.h>
#include <stdlib.h>

void bargraph(int number)
{
int x;
cin >>x;
{for( ; x>0; x--)
     cout <<"*";
     }
     }


int main()
{
int a;
cin>> a;

  bargraph (a);



      system("PAUSE");
      return 0;
}

The last assignment for this program is to modify this code. The new program should use a function, for loop, and an array of maximum size 20. The user defines how many numbers are input and the output should be each number that was input. For example:

If the user defines 3 numbers and enters an input of 3, 4, 5 the output should be:

***
****
*****

I have made progress but still am not receiving the right output.

Code:

#include <iostream.h>
#include <stdlib.h>

void bargraph(int number)
{
for( int i=0; i <number; i++)
 cout <<"*";
 cout <<endl;
}


int main()
{
 int bar[20];
 int number;

 cout << "How many Numbers to Print Stars For? ";
 cin >> number;

 for(int i = 0; i < number; i++)
  {
  cout << "Enter a Number: ";
  cin >> bar[i];
  }

 bargraph(number);

      system("PAUSE");
      return 0;
}

Any suggestions would be greatly appreciated. Thanks.

>> I thought you declared a function first then did main then write what the funstion does.

It doesn't matter. Defining the function first is fine.

By the way, <iostream.h> and <stdlib.h> are deprecated. Use <iostream> and the std namespace.

Also, using for() without curly braces is bad.

Code:

for(int i = 0; i == WACKY_JOHNSON; ++i)
abc();
def();

What if you wanted to add ghi() to the loop?

Code:

for(int i = 0; i == WACKY_JOHNSON; ++i)
abc();
ghi();
def();

wouldn't work as expected. Always use curly braces.



Getting to the point: you only run bargraph() once. This will only print the bar graph for the last number entered. Also, all the values are stored in bar[]; but you do bargraph() on number. You need two loops: one for number input, and one to display a bar for each number.

If you have a problem, try running through each step of the program in your mind to see if it's doing what you want.

>> By the way, <iostream.h> and <stdlib.h> are deprecated.
<iostream.h> is not deprecated, it is completely non-standard. <stdlib.h> is deprecated and so it will work on all standards compliant compilers.

So the program is now doing what it is supposed to do, except that it outputs the stars after entering a number. I can't figure out how to get it to print out the stars after all of the numbers have been entered.

Code:

#include <iostream.h>
#include <stdlib.h>

 void bargraph(int number)
{
for( int i=0; i <number; i++)
 cout <<"*";
 cout <<endl;
}


int main()
{
 int bar[20];
 int number;

 cout << "How many Numbers to Print Stars For? ";
 cin >> number;

 for(int i = 0; i < number; i++)
  {
  cout << "Enter a Number: ";
  cin >> bar[i];
  bargraph(bar[i]);
  }

      system("PAUSE");
      return 0;
}

If you want to gather all the numbers up first, and then go through all the numbers and do the bar graph second, then it would make sense to separate those two tasks instead of putting them next to each other in the same loop.

Think about it without the code. How would you accomplish the task if you had to ask somebody for 20 numbers, and you had to write down the numbers he said, then you had to draw a bar for each number in the graph? If you can write that out in English how you would accomplish that task, in as much detail as you are capable of giving, then that would greatly help you solve the problem.

I get an error message because bar[i] is not declared outside the for loop.

Why? Because i is not declared. Just run the same loop again, this time not asking for each number, but printing the bar graph for each number.

You seriously need to brush up on your program design skills.

I get an error message because bar[i] is not declared outside the for loop.

Why? Because i is not declared. Just run the same loop again, this time not asking for each number, but printing the bar graph for each number.

You seriously need to brush up on your algorithm design skills.

I get an error message because bar[i] is not declared outside the for loop.

Why? Because i is not declared. Just run the same loop again, this time not asking for each number, but printing the bar graph for each number.

You seriously need to brush up on your algorithm design skills.

I followed your suggestions and added the following for loop to the end of the program:

Code:

 
for(int i = 0; i < number; i++)
  {
  bargraph(bar[i]);
  }

It now works how it is supposed to. Thanks for the help again.

You seriously need to brush up on your algorithm design skills.

The class I'm taking is just a "sample" of the programming I will have to do in the next course. As a beginner, I do not have much experience. Over time, I will learn the best/correct way to plan an algorithm and write a program. After all, practice makes perfect.