int main(int argc, const char * argv[])
{
string infix,postfix;
double result;
cout<<"Enter an infixed expression:- ";
cin>>infix;
postfix=InfixToPostfix(infix);
cout<<"\nPostfix expression:- "<<postfix;
result=postfixEvaluation(postfix);
cout<<"\nResult evaluation:- "<<result;
return 0;
}
int mybc()
{
char infix[SIZE];
int i,j=0;
push('#');
gets(infix); //Scan the infix expression
while(strcmp(infix,"quit")) //Scan for infix expressions and convert them to postfix expressions until the user wants to quit.
{
//Convert the infix expression to postfix.
for(i=0;infix[i]!='\0';i++)
{
if(isalnum(infix[i])) //If the current symbol is a digit or an alphabet, then add it to the postfix expression.
sufix[j++]=infix[i];
else if(infix[i]=='(') //If the current symbol is a (, then push it onto the stack.
push(infix[i]);
else if(infix[i]==')') //If the current symbol os a ), then pop all the elements from the stack and add them to the postfix until ( is found.
{
while(s[top]!='(')
sufix[j++]=pop();
pop();
}
else //If the current symbol is an operator, then pop all the elements from the stack which have a priority greater than the the current symbol.
{
while(prior(s[top])>=prior(infix[i]))
sufix[j++]=pop();
push(infix[i]);
}
}
while(s[top]!='#') //Pop all the elements from the stack.
sufix[j++]=pop();
sufix[j]='\0';
postfixEvaluation(); //Evaluate the postfix expression.
j=0;
top=-1;
push('#');
gets(infix);
}
return 0;
}
/*************************************************************
* Function: pa3_main ()
* Created: February 6th, 2012
* Last Revised: February 10th, 2012
* Description: This function runs an evaluation/conversion
* Input parameters: whether the expression should be saved
* Returns: N/A
* Preconditions: an expression needs to be converted/evaluated
* Postconditions: an expression has been converted/evaluated
*************************************************************/
void pa3_main (Bool isSaving)
{
FILE *outFile = NULL;
char infixString[128] = "", infixBackup[128],
postfixString[128], postfixBackup[128];
int endValue = 0.0;
Bool success = false;
// flush the buffer (just in case)
_flushall ();
fflush(stdin);
// ask/get for an infix expression
printf ("Expression to evaluate (positive integers, infix format)? ");
while (!isdigit (infixString[0]))
{
gets (infixString);
}
printf ("Converting..");
// make a backup copy of the inputted expression
strcpy (infixBackup, infixString);
printf (".");
// convert infix to postfix
success = infixConvertor (infixString, postfixString);
if (success)
{
printf (".");
// make a backup copy of the postfix expression
strcpy (postfixBackup, postfixString);
printf (".");
// evaluate the expression
printf (".Converted...Evaluating..");
endValue = postfixEvaluation (&postfixString[0]);
printf (".Evaluated!\n\n");
// print the data
printf ("%s = %s = %d\n", infixBackup, postfixBackup, endValue);
// perform any necessary file operations if necessary
if (isSaving)
{
// open the save file (or create one if necessary)
outFile = fopen ("expressions.txt", "a");
// print expression data
fprintf (outFile, "%s = %s = %d\n", infixBackup, postfixBackup, endValue);
// print that data has been saved
printf ("Expression data has been saved!\n");
// close file
fclose (outFile);
}
}
else
{
// if something went wrong, say so
printf ("Failed to evaluate expression!\n");
}
// print a new line
printf ("\n");
// pause the screen
pause_clear (true, false);
}
