A little confused

[lavaboy]

insert

My Code
#include<stdio.h>
main()
{
   int a,b,c=0;
   while(c!='#')
   {
   printf("please enter a new sequence\n"); 
   a=getchar() - '0';
   b=getchar() - '0';
   c=getchar();
   if(c=='*')
   {
    int product=a*b;
    printf("(%d) * (%d) = (%d) \n",a,b,product);
   }
   if(c=='/')
   {
    int divider=a/b;
    printf("(%d) / (%d) = ( %d)\n",a,b,divider);
   }
    if(c=='+')
   {
    int add = a+b;
    printf("(%d) + (%d) = (%d)\n",a,b,add);
   }
    if(c=='-')
   {
    int subtract=a-b;
    printf("(%d) - (%d) = (%d)\n",a,b,subtract);
   }


   }
   printf("good bye");
}
I have to write code that terminates the program when '#' is included which I have done and when I type in 34+
it should display 3+4=7 and same with 34* it should display 3*4=12 where my error lies is that when I run the program through the while loop it gives me 
please enter a new sequence 
34+
3 + 4=7
please enter a new sequence 
34-
please enter a new sequence 
34-
please enter a new sequence 
please enter a new sequence 
34-
please enter a new sequence 
34-
3-4=-1

Can anyone tell me why it is like that and how to fix it im a confused C programmer

[anduril462]

After you input "34+", you press enter. That puts a newline ('\n') in the input buffer. So the actual input the program sees is "34+\n". That means the second time through the loop, when you enter "34-\n", a is '\n' (since it was left over from the previous time), b is '3' and c is '\4'. You don't have a valid operator, so it does nothing, and you have "-\n" left in the input buffer. The next time you enter "34*\n". But given the leftovers, a is '-', b is '\n' and c is '3'.

So, you need to "eat up the remaining characters after you read your two operands, and the operator. Use the getchar/loop trick here: FAQ > Flush the input buffer - Cprogramming.com.

[lavaboy]

I have not learnt this method yet in class is there a counter solution in order to fix this problem.

[anduril462]

I don't know what you mean by "counter solution". Counter like for counting 1, 2, 3, ...? Or counter meaning "against" like a fix? Did you read the link I posted (that red text is a link, click it)? Did you understand it? You just need to copy-paste from there the simple loop with the getchar in it.