// Postfix Evaluation
#include <stdio.h>
void sum();
void diff();
void mult();
void divide();
int stack[50], top = -1;
int main() {
 char st[30];
 int i;
 printf("Enter the postfix expression: ");
 scanf("%[^\n]s", st);
 for (i = 0; st[i] != '\0'; i++) {
 if (st[i] != ' ') {
 switch (st[i]) {
 case '+':
 sum();
 break;
 case '-':
 diff();
 break;
 case '*':
 mult();
 break;
 case '/':
 divide();
 break;
 default:
 top++;
 stack[top] = st[i] - '0';
 }
 }
 }
 printf("\nThe result is = %d\n", stack[top]);
 return 0;
}
void sum() {
 int res, op1, op2;
 op1 = stack[top];
 top--;
 op2 = stack[top];
 top--;
 res = op2 + op1;
 top++;
 stack[top] = res;
}
void diff() {
 int res, op1, op2;
 op1 = stack[top];
 top--;
 op2 = stack[top];
 top--;
 res = op2 - op1;
 top++;
 stack[top] = res;
}
void mult() {
 int res, op1, op2;
 op1 = stack[top];
 top--;
 op2 = stack[top];
 top--;
 res = op2 * op1;
 top++;
 stack[top] = res;
}
void divide() {
 int res, op1, op2;
 op1 = stack[top];
 top--;
 op2 = stack[top];
 top--;
 res = op2 / op1;
 top++;
 stack[top] = res;
}