4. Data Structure Program | Read Now → VTULOOP

Data Structure Lab Program -04

Design, Develop and Implement a Program in C for converting an Infix Expression to Postfix Expression. Program should support for both parenthesizedand free parenthesized expressions with the operators: +, -, *, /, %(Remainder), ^(Power) and alphanumeric operands.

Program-4 code [infinxtopostfix.c]

#include<stdio.h>
#include<string.h>

int F(char symbol)
{
 switch (symbol)
 {
 case '+':
 case '-':return 2;
 case '*':
 case '/':
 case '%':return 4;
 case '^':
 case '$':return 5;
 case '(':return 0;
 case '#':return -1;
 default :return 8;
 }
}

int G(char symbol)
{
 switch (symbol)
 {
 case '+':
 case '-':return 1;
 case '*':
 case '/':
 case '%':return 3;
 case '^':
 case '$':return 6;
 case '(':return 3;
 case ')':return 0;
 default :return 7;
 }
}

void infix_postfix(char infix[], char postfix[])
{
int top=-1, j=0, i;
char s[30], symbol;
s[++top] = '#';
for(i=0; i < strlen(infix); i++)
{
 symbol = infix[i];
 while (F(s[top]) > G(symbol))
 {
  postfix[j] = s[top--];
  j++;
 }
 if(F(s[top]) != G(symbol))
  s[++top] = symbol;
 else
  top--;
}
while(s[top] != '#')
 postfix[j++] = s[top--];
postfix[j] = '\0';
}

void main()
{
char infix[20], postfix[20];
printf("\nEnter a valid infix expression\n") ;
scanf ("%s", infix) ;
infix_postfix (infix, postfix);
printf("\nThe infix expression is:\n");
printf ("%s",infix);
printf("\nThe postfix expression is:\n");
printf ("%s",postfix) ;

}