85 lines
1.5 KiB
C
85 lines
1.5 KiB
C
#include <stdio.h>
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#include <string.h>
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#define MAX_SIZE 100
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int stack[MAX_SIZE];
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int top = -1;
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void push(int item)
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{
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if (top >= MAX_SIZE - 1)
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{
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printf("Stack Overflow\n");
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return;
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}
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stack[++top] = item;
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}
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int pop()
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{
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if (top < 0)
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{
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printf("Stack Underflow\n");
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return -1;
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}
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return stack[top--];
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}
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int isDigit(char c)
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{
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return c >= '0' && c <= '9';
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}
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int evaluatePostfix(char *exp)
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{
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int i, operand1, operand2, result;
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for (i = 0; exp[i] != '\0'; i++)
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{
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if (isDigit(exp[i]))
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{
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push(exp[i] - '0');
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}
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else
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{
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operand2 = pop();
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operand1 = pop();
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switch (exp[i])
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{
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case '+':
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push(operand1 + operand2);
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break;
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case '-':
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push(operand1 - operand2);
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break;
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case '*':
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push(operand1 * operand2);
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break;
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case '/':
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if (operand2 == 0)
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{
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printf("Error: Division by zero\n");
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return -1;
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}
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push(operand1 / operand2);
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break;
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}
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}
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}
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return pop();
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}
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int main()
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{
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char exp[MAX_SIZE];
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printf("Enter a postfix expression: ");
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gets(exp);
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int result = evaluatePostfix(exp);
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if (result != -1)
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{
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printf("Result: %d\n", result);
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}
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return 0;
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}
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