Infix to Postfix Implementation using c program

Data Structures using C Language / Infix to Postfix Implementation using c program

Program

#include<stdio.h>
#include<string.h>
char stack[50];
int top=-1;
void post(char infix[]);
void push(char);
char pop();

void main()
{
char infix[25];
printf("\nEnter a Infix Expression : ");
gets(infix);
post(infix);
getch();
}

void push(char symb)
{
if(top>=49)
{
printf("\nStack Overflow");
getch();
return;
}
else
{
top=top+1;
stack[top]=symb;
}
}

char pop()
{
char item;
if(top==-1)
{
printf("\nStack is Empty");
getch();
return(0);
}
else
{
item=stack[top];
top--;
}
return(item);
}

int preced(char ch)
{
if(ch==47) return(5);
else if(ch==42) return(4);
else if(ch==43) return(3);
else return(2);
}

void post(char infix[])
{
int l, index=0,pos=0;
char symbol,temp,postfix[40];
l=strlen(infix);
push('#');

while(index<l)
{
symbol=infix[index];
switch(symbol)
{
case '(': push(symbol);break;
case ')': temp=pop();while(temp!='(')
{
postfix[pos]=temp;
pos++;
temp=pop();
}
break;
case '+':
case '-':
case '*':
case '/':
case '^':
while(preced(stack[top])>=preced(symbol))
{
temp=pop();
postfix[pos]=temp;
pos++;
}
push(symbol);break;

default: postfix[pos++]=symbol;break;
}
index++;
}
while(top>0)
{
temp=pop();
postfix[pos++]=temp;
}
postfix[pos++]='\0';
puts(postfix);
return;
}

Output

Enter a Infix Expression: (a+b)+c
ab+c+

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