postfix_expression

 #include<stdio.h>

#include<conio.h>

int stack[20];

int top=-1;

void push(int x)

{

stack[++top]=x;

}

int pop()

{

return stack[top--];

}

void main(){

char exp[20];

char *e;

int n1,n2,n3,num;

clrscr();

printf("Enter the expression::");

scanf("%s",exp);

e=exp;

while(*e !='\0')

{

if(isdigit(*e))

{

num=*e-48;

push(num);

}

else

{

n1=pop();

n2=pop();

switch(*e)

{

case '+':n3=n2+n1;

break;

case '-':n3=n2-n1;

break;

case '*':n3=n2*n1;

break;

case '/':n3=n2/n1;

break;

}

push(n3);

}

e++;

}

printf("\n The result of expression %s=%d\n\n",exp,pop());

getch();

}