Program Problem

[Budgiekarl]

My mom got me a good book on C I've been learning alot! And I wanted to make this calculor with a menu, and you type 1 to add some numbers, then it asks you for how many numbers you want to add, then you type in the value.

The problem is that some times when it's asking you what the numbers you want to add(not to be confued with HOW MANY numbers you want to add)you type in the value and press enter and it add another line and you have to add another number to goto the next one I've got a screen shot to show you:

http://mksoftg.tripod.com/CS.mks


(the screen shot is a bit messed up but you can see the problem area)

and when it add it all up it prints a big number!

heres the code:

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

main()
{
  int choice, numAdd, temp, numTotal = 0;
    
  printf("Welcome to Karl's easy math Calculator!\n\n");
  
  do
  {
   printf("1: Add\n2: Subtact\n3: drivde\n4: Exit\n\nWhat you want to do?\n");
   scanf(" %d",&choice); 
   /******************************************/
   switch (choice)
   {
      case (1) : { printf("How many numbers are you going to add?\n");
                   scanf("%d", &numAdd);
                      /******************************************/
                      for(; numAdd > 0; numAdd--)
                      {
                         printf("Whats a number that you want to add?");
                         
                         scanf("%d ", &temp);
                         
                         numTotal += temp;
                         temp = 0;
                      }
                      /******************************************/
                   printf("Thats up to %d\n\n", &numTotal);
                   break;
                   }
                   
      default : { printf("Unknown Number, plaese type again"); }  
   }
   /******************************************/
  } while ((choice < 1) || (choice > 4));
  
  
  system("PAUSE");	
  return 0;
}

Note: I'm useing Dev-Cpp so I don't know if this code will work on all compilers...

as you can see, it's not done yet, I want to get pass this first.

plx reply, thx

[ronin]

just a couple things outta place.... I *think*

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

int main()
{
  int choice, numAdd, temp, numTotal = 0;
    
  printf("Welcome to Karl's easy math Calculator!\n\n");
  
  do
  {
   printf("1: Add\n2: Subtact\n3: drivde\n4: Exit\n\nWhat you want to do?\n");
   scanf("%d%*c",&choice); 
   /******************************************/
   switch (choice)
   {
      case 1 : { printf("How many numbers are you going to add?\n");
                 scanf("%d", &numAdd);
                      /******************************************/
                      for(; numAdd > 0; numAdd--)
                      {
                         printf("Whats a number that you want to add?");
                         
                         scanf("%d%*c", &temp);
                         
                         numTotal += temp;
                         temp = 0;
                      }
                      /******************************************/
                   printf("Thats up to %d\n\n", numTotal);
                   
                   } 
                   
                   break;
                   
      default : { printf("Unknown Number, plaese type again"); }   break;
   }
   /******************************************/
  } while ((choice < 1) || (choice > 4));
  
  
  system("PAUSE");	
  return 0;
}

[WaltP]

You need to zero your total accumulator 'numTotal' at the top of you do loop, otherwise your second run will be added to your first total.

The change ronin mentions:
scanf("%d%*c", &temp);
was not necessary with my compiler, but might be with yours. I rarely used scanf because it can be a little ideosyncratic depending on the compiler. Try printing the value read immediately after the scanf to check it.

Alternatively, uset gets() or fgets() to enter a string which will read off the CRLF too and use the function atoi() to convert it to a number.

[Budgiekarl]

Thx, now it works!

WaltP, could I do this:

for(numTotal = 0; numAdd > 0; numAdd--)

and ronin why do I need to do scanf("%d%*c", &temp); and all those's %'s?

[Hammer]

>>could I do this:
>>for(numTotal = 0; numAdd > 0; numAdd--)
Yes, if you want to.

>>why do I need to do scanf("%d%*c", &temp); and all those's %'s?
It's a poor mans version of obtaining a number from the user.

[ronin]

Originally posted by Hammer
>>why do I need to do scanf("%d%*c", &temp); and all those's %'s?
It's a poor mans version of

Hmph that hurt.

yea, it's just a crude way to eat the '\n' that was left in the input buffer after getting the int data type.

[Hammer]

Nothing personal, ronin

But if you are going to use scanf(), at least ensure you check it's return code.