usaa20/a2/program.c

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

struct stack{
    char data[100];
    int size;
}s;

void push(char ch){

    if(s.size < 100){
        assert(s.size < 100);
        s.size++;
        s.data[s.size] = ch;
    }
    else{
        exit(0);

    }

} 

void pop(){
    if(s.size > 0){
        assert(s.size > 0);
        s.size--;
    }
    else {
        exit(0);
    }
}

bool find_pair(char a, char b){
    if(a == '(' && b == ')') 
        return true;
    else if(a == '{' && b == '}')
        return true;
    else if(a == '<' && b == '>')
        return true;
    else if(a == '[' && b == ']')
        return true;

    return false;

}
char right_pair(char a){
    char b;
    if(a == '('){
        b = ')';
    }
    else if(a == '{'){
        b = '}';
    }
    else if(a == '['){
        b = ']';
    }
    else if(a == '<'){
        b = '>';
    }
    return b;    

}

char gettop(){
    return s.data[s.size];
}

int main(){
    
    //struct stack mystack;
    //memset(&mystack, 0 , sizeof(struct stack));
    char line[100];
    s.size = -1;
    char *x = fgets(line, 100, stdin);

    int l = strlen(line);
    int i, j;
        

    for(i = 0; i < l; i++){
        if(line[i] == '{' || line[i] == '(' || line[i] == '[' || line[i] == '<'){
            push(line[i]);
        }
        else if(line[i] == '}' || line[i] == ')' || line[i] == ']' || line[i] == '>'){   
         char a = gettop();
         //printf("%c", a);
         if(!find_pair(gettop(), line[i])){
             char b = right_pair(a);
             printf("Crossed bracket %c in %d, expected %c\n", line[i], i, b);
             return 0;            

         }
         else{
             pop();
         }

        }
    }
    printf("All brackest are OK\n");
  


    return 0;
}