#define STACK_SIZE 100
#include <stdio.h>

char stack[STACK_SIZE];
int sp=0;


/*
 * Pushes character c onto the stack.
 * Returns 0 if successful.
 * Returns -1 if an error occurs.  (Stack full).
 */
int push (char c)
{
  if(sp < STACK_SIZE){
    stack[sp] = c;
    sp++;
    return 0;
  }
  else{
    return -1;
  }
    // TODO
}

/*
 * Pops next character off the stack.
 * Returns the char if successful.
 * Returns -1 if an error occurs.  (Stack empty).
 */
int pop ()
{
  if(sp == 0){
    return -1;
  }
  else{
    sp--;
    return stack[sp];
  }
  // TODO
}

/*
 * Returns the current size of the stack.
 */
int stackSize()
{
  return sp;
    // TODO
}

/*
 * Tests if the stack is correctly implemented
 */
int main ()
{
  int good = 0;
  int linecount = 0;
  int charcount = 0;
  int currentchar;
  int line = 0;
  int position = 0;
  char c = getChar();
  while(c != EOF){
    currentchar = push(c);
    if(c == "(" || c == "[" || c == "{"){
      if(currentchar == -1){
    printf("Error: Stack Full!");
    pop();
    good = 1;
    break;
      }
    }
    else if(c == ")" && pop() == -1){
      printf("Line %d, Char %d: Found ). No matching character.");
      break;
      good = 1;}
    else if(c == "}" && pop() == -1){
      printf("Line %d, Char %d: Found }. No matching character.");
      break;
      good = 1;}
    else if(c == "]" && pop() == -1){
      printf("Line %d, Char %d: Found ]. No matching character.");
      break;}
    else if(c == '\0' && currentchar == "("){
      printf("Error: Expecting ), found end of input");
      break;}
    else if(c == '\0' && currentchar == "{"){
      printf("Error: Expecting }, found end of input");
      break;
      good = 1;}
    else if(c == '\0' && currentchar == "["){
      printf("Error: Expecting ], found end of input");
      break;
      good = 1;}
    else if(c == '\n')
      linecount++;
    else if(c == ")" && currentchar == "("){
      pop();
      charcount++;}
    else if(c == ")" && currentchar == "{"){
      printf("Line: %d, Char %d: Found ), expected }", linecount, charcount);
      pop();
      break;
      good = 1;}
    else if(c == ")" && currentchar == "["){
      printf("Line: %d, Char %d: Found ), expected ]", linecount, charcount);
      pop();
      break;
      good = 1;}
    else if(c == "}" && currentchar == "{"){
      pop();
      charcount++;}
    else if(c == "}" && currentchar == "("){
      printf("Line: %d, Char %d: Found }, expected )", linecount, charcount);
      pop();
      break;
      good = 1;}
    else if(c == "}" && currentchar == "["){
      printf("Line: %d, Char %d: Found }, expected ]", linecount, charcount);
      pop();
      break;
      good = 1;}
    else if(c == "]" && currentchar == "["){
      pop();
      charcount++;}
    else if(c == "]" && currentchar == "("){
      printf("Line: %d, Char %d: Found ], expected )", linecount, charcount);
      pop();
      break;
      good = 1;}
    else if(c == "]" && currentchar == "{"){
      printf("Line: %d, Char %d: Found ], expected }", linecount, charcount);
      pop();
      break;
      good = 1;}
    c = getChar();
  }
  if(good == 0)
    printf("Well formatted input.");
}