C Program for Infix to Postfix Equivalent

1			#include<stdio.h>
2			void infixtopostfix(char[],char[]);
3			int precedence(char);
4			void main()
5			{
6			char infix[20],postfix[20];
7			//clrscr();
8			printf("\n Enter the Infix_experssion : ");
9			scanf("%s",infix);
10			infixtopostfix(infix,postfix);
11			printf("\nPostfix_expression is : %s",postfix);
12			}
13			void infixtopostfix(char infix[],char postfix[])
14			{
15			char s[20],symbol;
16			int top=-1,i=0,j=0;
17			while(infix[i]!='\0')
18			{
19			symbol=infix[i];
20			switch(symbol)
21			{
22			case '(': ++top;
23			s[top]=symbol;
24			break;
25			case ')': while(s[top]!='(')
26			{
27			postfix[j++]=s[top];
28			top--;
29			}
30			top--;
31			break;
32			case '+':
33			case '-':
34			case '*':
35			case '^':
36			case '/':
37			while(precedence(symbol)<=precedence(s[top])&&top!=-1)
38			postfix[j++]=s[top--];
39			s[++top]=symbol;
40			break;
41			default:postfix[j++]=symbol;
42			}
43			i++;
44			}
45			while(top!=-1)
46			{
47			postfix[j++]=s[top];
48			top--;
49			}
50			postfix[j]='\0';
51			}
52			int precedence(char x)
53			{
54			switch(x)
55			{
56			case '+':
57			case '-': return(1);
58			case '*':
59			case '^': return(3);
60			case '/': return(2);
61			default: return(0);
62			}
63			}
			Output:
			Enter the Infix_experssion : a+b*c
			Post fix_expression is : abc*+
			Enter the Infix_experssion : a+(b+c*d)*f
			Post fix_expression is : abcd*+f*+
			Enter the Infix_experssion : a+(b*c+d)*f
			Post fix_expression is : abc*d+f*+
			Enter the Infix_experssion : a*(b*c+d)+f
			Post fix_expression is : abc*d+*f+