casting

[manichandra]

i want to pass two characters("6","8") into a function which will convert this two chars into integers and add these two integers(6+8=14) after that it will change the value (int 14) into char (char "14")  and returns the char.
can anybody help me please ??

[Stefan Pendl]

Could you post the complete assignment?

[CommonTater]

What have you tried so far?

Post up a little code for us to look at.

[manichandra]

One way to evaluate a prefix expression is to use a queue. To evaluate the expression, scan it repeatedly until the final expression value is known. In
each scan, read the tokens and store them in a queue. In each scan, replace an operator followed by two operands by the calculated values.
For example, the following expression is a prefix expression, which is evaluated to 159.
-+*9+28*+4863
We scan the expression and score it in a queue. During the scan, when an operator is followed by two operands, such as + 2 8, we put the result, 10 in the queue.
After the first scan, we have - + * 9 10 * 12 6 3
After the second scan, we have - + 90 72 3
After the third scan, we have - 162 3
After the fourth scan, we have 159

this is the question

[CommonTater]

And what have you tried?

(Show us your code...)

[manichandra]

THIS IS THE CODE SO FAR I TRIED.


int calculate(char a, char b, char c)
{
    int n,p;
    n=(int)a-48;
    p=(int)b-48;
    if(a=='+')
        return (n+p);
   
    else if(a=='-')
        return (n-p);
    else if(a=='*')
        return (n*p);
    else if(a=='/')
        return (n/p);
}

int main()
{
    char expr[]="-+9+28*+4863";
    QUEUE *q = CreateQueue();
    int i=0,j=1,k=2;
    int r;
    char dataout,data;
   
    while((expr!='\0'))
    {
        if(ispunct(expr)&&isdigit(expr[j])&&isdigit(expr[k]))
       
           {
               r=calculate(expr,expr[j],expr[k]);
               data='0'+r;
               Enqueue(q, data);
               i=i+3;j=j+3;k=k+3;
           }
        else
        {
            Enqueue(q,expr);
            i++;j++;k++;
        }
    }
   
   
    while(!EmptyQueue(q))
          {
              NODE *temp = q->front;
              dataout=q->front->data;
              printf("%c",dataout);
              q->front=q->front->link;
              q->count--;
              free(temp);
          }
           

    return 0;
}

[manichandra]

this is my updated code. will it work ??
compete code is in my  attached my ".c" file



int calculate(char a, int b, int c)
{
   
    if(a=='+')
        return (b+c);
   
    else if(a=='-')
        return (b-c);
    else if(a=='*')
        return (b*c);
    else if(a=='/')
        return (b/c);
}

int main()
{
    char expr[]="-+9+28*+4863";
    QUEUE *q = CreateQueue();
    char data1[8],data2[8],data[8];
    int i=0,j=1,k=2;
    int a,b,r;
    char *dataout,*datain;
   
    while((expr!='\0'))
    {
        if(ispunct(expr)&&isdigit(expr[j])&&isdigit(expr[k]))
       
           {
               data1[0]=expr[j];data1[1]='\0';
               data2[0]=expr[k];data2[1]='\0';
               
               a=atoi(data1);b=atoi(data2);
               r=calculate(expr,a,b);
               itoa (r, data, 10);
               datain=data;
               Enqueue(q, datain);
               i=i+3;j=j+3;k=k+3;
           }
        else
        {
            data[0]=expr;data[1]='\0';
            datain=data;
            Enqueue(q,datain);
            i++;j++;k++;
        }
    }
   
   
    while(!EmptyQueue(q))
          {
              NODE *temp = q->front;
              strcpy(dataout,q->front->data);
              printf("%s",dataout);
              q->front=q->front->link;
              q->count--;
              free(temp);
          }
           

    return 0;
}



and my compiler is showing an error

"implict declaration of function iota in is invalid in C99".
i am using Xcode in mac OS X

[CommonTater]

and my compiler is showing an error

"implict declaration of function iota in is invalid in C99".
i am using Xcode in mac OS X

This isn't an X-Code support forum.

If you're getting a compiler error... then your code obviously doesn't work.

[manichandra]

Thanks.
what i meant is will it work in other compilers ??
i replaced itoa with "sprintf(data,"%d",r);"
it seems to be working.