92 lines
1.6 KiB
C
92 lines
1.6 KiB
C
#include <stdio.h>
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#include <string.h>
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#define MAX_SIZE 100
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char stack[MAX_SIZE];
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int top = -1;
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void push(char 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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char 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 precedence(char symbol)
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{
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switch (symbol)
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{
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case '^':
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return 3;
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case '*':
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case '/':
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return 2;
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case '+':
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case '-':
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return 1;
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default:
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return 0;
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}
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}
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void infixToPostfix(char infix[], char postfix[])
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{
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int i, j = 0;
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char symbol, next;
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for (i = 0; i < strlen(infix); i++)
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{
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symbol = infix[i];
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if ((symbol >= 'a' && symbol <= 'z') || (symbol >= 'A' && symbol <= 'Z') || (symbol >= '0' && symbol <= '9'))
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{
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postfix[j++] = symbol;
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}
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else if (symbol == '(')
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{
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push(symbol);
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}
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else if (symbol == ')')
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{
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while ((next = pop()) != '(')
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{
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postfix[j++] = next;
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}
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}
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else
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{
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while (top > -1 && precedence(stack[top]) >= precedence(symbol))
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{
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postfix[j++] = pop();
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}
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push(symbol);
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}
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}
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while (top > -1)
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{
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postfix[j++] = pop();
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}
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postfix[j] = '\0';
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}
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int main()
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{
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char infix[MAX_SIZE], postfix[MAX_SIZE];
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printf("Enter infix expression: ");
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gets(infix);
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infixToPostfix(infix, postfix);
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printf("Postfix expression: %s\n", postfix);
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return 0;
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} |