DS 5A - SUFFIX EXPRESSION

5. Design, Develop and Implement a Program in C for the following Stack Applications 

a. Evaluation of Suffix expression with single digit operands and operators: +, -, *, /, %, ^

suffix.c - PROGRAM

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

float compute(char symbol, float op1, float op2)
{
switch (symbol)
{
case '+': return op1 + op2;
case '-': return op1 - op2;
case '*': return op1 * op2;
case '/': return op1 / op2;
case '$':
case '^': return pow(op1,op2);
default : return 0;
}
}

void main()
{
float s[20], res, op1, op2;
int top, i;
char postfix[20], symbol;
printf("\nEnter the postfix expression:\n");
scanf ("%s", postfix);
top=-1;
for (i=0; i<strlen(postfix) ;i++)
{
symbol = postfix[i];
if(isdigit(symbol))
s[++top]=symbol - '0';
else
{
op2 = s[top--];
op1 = s[top--];
res = compute(symbol, op1, op2);
s[++top] = res;
}
}
res = s[top--];
printf("\nThe result is : %f\n", res);

}