usaa24/a1/program.c

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

int isOpening(char c) {
    return c == '{' || c == '[' || c == '(' || c == '<';
}

int isClosing(char c) {
    return c == '}' || c == ']' || c == ')' || c == '>';
}

int isMatching(char open, char close) {
    return (open == '{' && close == '}') ||
           (open == '[' && close == ']') ||
           (open == '(' && close == ')') ||
           (open == '<' && close == '>');
}

char expectedClosing(char open) {
    if (open == '{') return '}';
    if (open == '[') return ']';
    if (open == '(') return ')';
    if (open == '<') return '>';
    return '\0';
}

int main() {
    char input[101];
    char stack[100];
    int top = -1;

    fgets(input, 101, stdin);

    printf("Read: %s", input);

    for (int i = 0; i < strlen(input); i++) {
        char current = input[i];

        if (isOpening(current)) {
            if (top < 99) {
                stack[++top] = current;
            } else {
                printf("Stack is full\n");
                return 1;
            }
        } else if (isClosing(current)) {
            if (top == -1) {
                printf("Unexpected closing bracket %c in %d\n", current, i);
                return 0;
            }
            if (!isMatching(stack[top], current)) {
                char expected = expectedClosing(stack[top]);
                printf("Crossed bracket %c in %d, expected %c\n", current, i, expected);
                return 0;
            }
            top--;
        }
    }

    if (top != -1) {
        printf("Missing closing brackets: ");
        while (top != -1) {
            printf("%c", expectedClosing(stack[top--]));
        }
        printf("\n");
        return 0;
    }

    printf("All brackets OK\n");
    return 0;
}