Code - Bracket Matching partial implementation

// Author: Dean Wunder (d.wunder@unsw.edu.au)
// Implementation in Live Stream by Marc Chee (November 2020)
// Implementation wasn't tested, but will hopefully mostly work!

// Using a stack to match brackets

#include <stdio.h>
#include "stack.h"

int opening_bracket(int bracket);
int closing_bracket(int bracket);
int brackets_match(int opening, int closing);

int main(int argc, char *argv[]) {

    // make a stack
    // loop through argv[1]
    // for each element, if it's opening, add it to the stack
    // if it's closing, pop from the stack if they match
    // if they don't match, report invalid
    
    Stack bracket_stack = create_stack();
    
    int i = 0;
    while (argv[1][i] != '\0') {
        if (opening_bracket(argv[1][i])) {
            // it's an opening bracket, add it to the stack
            stack_push(bracket_stack, argv[1][i]);
        } else if (closing_bracket(argv[1][i])) {
            // it's a closing bracket, check if it matches
            // the most recent opening bracket
            if (stack_size(bracket_stack) <= 0) {
                // No more opening brackets in the stack to match
                // this closing bracket
                printf("Invalid string, brackets didn't match.\n");
                return 1;
            }
            int top = stack_pop(bracket_stack);
            if (brackets_match(top, argv[1][i])) {
                // brackets matched
            } else {
                // brackets didn't match . . . we have an invalid string
                printf("Invalid string, brackets didn't match.\n");
                return 1;
            }
        }
    }
    if (stack_size(bracket_stack) == 0) {
        printf("All brackets match!\n");
    } else {
        printf("Invalid string, brackets didn't match.\n");
        return 1;
    }
    
    
    return 0;
}

int opening_bracket(int bracket) {
    if (bracket == '(' || bracket == '{' || bracket == '[') {
        return 1;
    }
    return 0;
}

int closing_bracket(int bracket) {
    if (bracket == ')' || bracket == '}' || bracket == ']') {
        return 1;
    }
    return 0;
}

int brackets_match(int opening, int closing) {
    if (opening == '(' && closing == ')') {
        return 1;
    }
    if (opening == '{' && closing == '}') {
        return 1;
    }
    if (opening == '[' && closing == ']') {
        return 1;
    }
    return 0;
}