Create evaluation_of_postfix_expression.c

Author: santhosh-programmer

evaluation_of_postfix_expression.c

@@ -0,0 +1,60 @@
+
+//Give an input Postfix Expression, write the program to evaluate the given postfix expression using Stack Operations.
+
+//Input : Postfix Expression and List of values of the variables
+
+//Output : Result of the expression
+
+#include<stdio.h>
+#include<stdlib.h>
+#include<string.h>
+int s[20],top=-1;
+void push(int e)
+{
+    top++;
+    s[top]=e;
+}
+int pop()
+{
+    int temp=top;
+    top--;
+    return s[temp];
+}
+int main()
+{
+    char str[20];
+    int a,n,b,c;
+    scanf("%s",str);
+    for(int i=0;i<strlen(str);i++)
+    {
+        if(str[i]>='a' && str[i]<='z')
+        {
+            scanf("%d",&n);
+            push(n);
+        }
+        else
+        {
+            switch(str[i])
+            {
+                case '+':  a=pop()+pop();
+                           push(a);
+                           break;
+                case '-':  b=pop();
+                           c=pop();
+                           a=c-b;
+                           push(a);
+                           break;
+                case '*':  a=pop()*pop();
+                           push(a);
+                           break;
+                case '/':  b=pop();
+                           c=pop();
+                           a=c/b;
+                           push(a);
+                           break;
+            }
+        }
+    }
+    printf("%d",pop());
+    return 0;
+}