how do i overcome Stack Exception processor fault in ths program........?

[Sai Vamshi]

#include<stdio.h>
#include<stdlib.h>
void main()
{
char istr[100],tstack[100],ostr[100];
int i=0,top=0,j=0;
printf("Enter the infix expression...\n");
scanf("%s",&istr);
printf("The infix expression is :%s\n",istr);
while(istr[i]!='\0')
{
switch(istr[i])
{
case '^':
case '%':
case '/':
case '*':
            if(tstack[top]=='+'||tstack[top]=='-'||tstack[top]=='(')
            {
            top++;
            tstack[top]=istr[i];
            }
            else if(tstack[top]=='\0')
            tstack[top]=istr[i];
            else
            {
            while(tstack[top]!='\0')
            {
            ostr[j]=tstack[top];
            top--;
            j++;
            }
            if(top==-1)
            top++;
            tstack[top]=istr[i];
            }
            break;
case '+':
case '-':
            if(tstack[top]=='(')
            {
            top++;
            tstack[top]=istr[i];
            }
         else if(tstack[top]=='\0')
            tstack[top]=istr[i];
            else
            {
            while(tstack[top]!='\0')
            {
            ostr[j]=tstack[top];
            top--;
         j++;
            }
            if(top==-1)
            top++;
            tstack[top]=istr[i];
            }
            break;
case '(':if(tstack[top]=='\0')
            tstack[top]=istr[i];
            else
            {
            top++;
            tstack[top]=istr[i];
            }
            break;
case ')':while(tstack[top]!='(')
            {
            ostr[j]=tstack[top];
            top--;
            j++;
            }
            tstack[top]='\0';
            top--;
            break;
default :ostr[j]=istr[i];
            j++;
            break;
}
i++;
}
while(top!=-1)
{
ostr[j]=tstack[top];
top--;
j++;
}
printf("The postfix expression is :%s",ostr);
}

[zmbd]

We do not have your data nor CPU to compile and run so:
What troubleshooting, if any, have you already done?
What is the error code you are receiving - several reasons for stack exceptions?
At what line is your code faulting?

[weaknessforcats]

The first thing I notice is all the arrays are 100 elements but nowhere in the code is there a check to see if top++, i++, or j++ goes over 99. Also, top--is never checked to see a negative value occurs.

This is an excellent time to use your debugger and step through the code.