MIT-Curricular/DS/C/Lab/Week6/PrefixToPostfix.c

63 lines
1.4 KiB
C

#include <stdio.h>
#include <string.h>
#define MAX_SIZE 100
char stack[MAX_SIZE][MAX_SIZE];
int top = -1;
void push(const char* item) {
if (top >= MAX_SIZE - 1) {
printf("Stack Overflow\n");
return;
}
strcpy(stack[++top], item);
}
char* pop() {
if (top < 0) {
printf("Stack Underflow\n");
return NULL;
}
return stack[top--];
}
int isOperator(char c) {
return (c == '+' || c == '-' || c == '*' || c == '/');
}
int isAlphanumeric(char c) {
return ((c >= '0' && c <= '9') || (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z'));
}
void prefixToPostfix(char* prefix) {
int len = strlen(prefix);
char temp[MAX_SIZE];
for (int i = len - 1; i >= 0; i--) {
if (isAlphanumeric(prefix[i])) {
temp[0] = prefix[i];
temp[1] = '\0';
push(temp);
} else if (isOperator(prefix[i])) {
char op1[MAX_SIZE], op2[MAX_SIZE], result[MAX_SIZE];
strcpy(op1, pop());
strcpy(op2, pop());
sprintf(result, "%s%s%c", op1, op2, prefix[i]);
push(result);
}
}
printf("Postfix expression: %s\n", stack[top]);
}
int main() {
char prefix[MAX_SIZE];
printf("Enter prefix expression: ");
fgets(prefix, MAX_SIZE, stdin);
prefix[strcspn(prefix, "\n")] = 0; // Remove newline if present
prefixToPostfix(prefix);
return 0;
}