usaa24/a1/program.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_LENGTH 100

// Function to check if two brackets are matching
int isMatching(char opening, char closing) {
    return (opening == '{' && closing == '}') ||
           (opening == '[' && closing == ']') ||
           (opening == '(' && closing == ')') ||
           (opening == '<' && closing == '>');
}

// Function to get the expected closing bracket for a given opening bracket
char getExpectedClosingBracket(char opening) {
    return (opening == '{') ? '}' :
           (opening == '[') ? ']' :
           (opening == '(') ? ')' :
           (opening == '<') ? '>' : '\0';
}

int main() {
    char input[MAX_LENGTH + 1];
    char stack[MAX_LENGTH];
    int top = -1; // Stack pointer
    int foundBracket = 0; // Flag to check if any bracket is found

    // Reading the string
    fgets(input, sizeof(input), stdin);
    
    // Remove newline character if present
    input[strcspn(input, "\n")] = 0;

    // Check if string length exceeds MAX_LENGTH
    if (strlen(input) > MAX_LENGTH) {
        printf("Error: Input length exceeds 100 characters.\n");
        return 1;
    }

    // Print the input line for the output format
    printf("Read: %s\n", input);

    // Iterating over each character in the string
    for (int i = 0; i < strlen(input); i++) {
        char current = input[i];

        // Check if current character is an opening bracket
        if (current == '{' || current == '[' || current == '(' || current == '<') {
            stack[++top] = current; // Push to stack
            foundBracket = 1; // Found at least one bracket
        } 
        // If current character is a closing bracket
        else if (current == '}' || current == ']' || current == ')' || current == '>') {
            // If stack is empty, it's an error
            if (top == -1) {
                printf("Unexpected closing bracket %c in %d\n", current, i);
                return 0;
            }

            // If brackets do not match, it's an error
            if (!isMatching(stack[top--], current)) {
                printf("Crossed bracket %c in %d, expected %c \n", current, i, 
                       getExpectedClosingBracket(stack[top + 1]));
                return 0;
            }
        }
    }

    // If there are unmatched opening brackets left in the stack
    if (top != -1) {
        printf("Missing closing brackets: ");
        for (int i = top; i >= 0; i--) {
            printf("%c", getExpectedClosingBracket(stack[i]));
        }
        printf("\n");
        return 0;
    }

    // If no brackets are found, output a success message
    if (!foundBracket) {
        printf("All brackets OK\n");
    } else {
        // Expected correct output if all brackets match
        printf("All brackets OK\n");
    }

    return 0;
}