ValidParentheses

struct Node{
    char brackett;
    struct Node* prev;
};

bool isValid(char* s) {
    struct Node* tempNode;
    struct Node* StackTop = NULL;
    char tempChar;
    char* sPtr = s;
    while(*sPtr != NULL){
        
        if(*sPtr == '(' || *sPtr == '{' || *sPtr == '[' ){          //push if next character is an open bracket
            tempNode = malloc( sizeof(struct Node) );          
            (*tempNode).brackett = *(sPtr);
            (*tempNode).prev = StackTop;
            StackTop = tempNode;


        }else{  
            //pop   StackTop holds the opening brackett
            if(StackTop == NULL){
                return false;
            }else{
                if((*StackTop).brackett + 0x1 == (*sPtr) || (*StackTop).brackett + 0x2 == (*sPtr) ){  
                    //compare StackTop char to string Pointer char 
                    //closing brackett is one or two away in the ascii table
                    //If value of StackTop is not a closing brackett then return false
                    //free()
                    StackTop = (*StackTop).prev;
                }else{
                    return false;
                }
            }
        } 
        sPtr++; 
    }
    return (StackTop == NULL);      //stack should be empty, return true if empty and false elsewise
}