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C Program To Convert Infix Expression To Postfix Expression: |
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#include
#include
#include
#include
#include
#define N 64
#define LP 10
#define RP 20
#define OPERATOR 30
#define OPERAND 40
// Left parentheses precedence. Minimum of all
#define LPP 0
// Addition Subtraction precedence. Minimum among all operator precedence
#define AP 1
#define SP AP
// Multiplication divisor precedence.
#define MP 2
#define DP MP
// Remainder precedence.
#define REMP 2
#define NONE 9
static char infix[N+1],stack[N],postfix[N+1];
static int top;
void infixtopostfix(void); /** POSTFIX CONVERSION FUNCTION **/
int gettype(char); /** TYPE OF EXPRESSION GENERATOR **/
void push(char); /** PUSH FUNCTION **/
char pop(void); /** POP FUNCTION **/
int getprec(char); /** PRECEDENCE CHECKER FUNCTION **/
void main()
{
char ch;
do
{
top=-1;
printf("\nEnter an infix expression\n");
fflush(stdin);
gets(infix);
infixtopostfix();
printf("\ninfix = %s\npost fix =%s\n",infix,postfix);
printf("\nDo you wish to continue\n");
ch=getche();
}while(ch=='Y' || ch=='y');
}
void infixtopostfix(void)
{
int i,p,l,type,prec;
char next;
i=p=0;
l=strlen(infix);
while(i-1 && prec <= getprec(stack[top]))
postfix[p++]=pop();
push(infix[i]);
break;
}
i++;
}
while(top>-1)
postfix[p++]=pop();
postfix[p]='\0';
}
int gettype(char sym)
{
switch(sym)
{
case '(':
return(LP);
case ')':
return(RP);
case '+':
case '-':
case '*':
case '/':
case '%':
return(OPERATOR);
default :
return(OPERAND);
}
}
void push(char sym)
{
if(top>N)
{
printf("\nStack is full\n");
exit(0);
}
else
stack[++top]=sym;
}
char pop(void)
{
if(top<=-1)
{
printf("\nStack is empty\n");
exit(0);
}
else
return(stack[top--]);
}
int getprec(char sym)
{
switch(sym)
{
case '(':
return(LPP);
case '+':
return(AP);
case '-':
return(SP);
case '*':
return(MP);
case '/':
return(DP);
case '%':
return(REMP);
default :
return(NONE);
}
}
SAMPLE INPUT AND OUTPUT:
Enter any infix expression
3*6+4*2/5
Infix = 3*6+4*2/5
Post fix =36*42*5/+
Do you wish to continue
y
Enter an infix expression
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