Lab 3

Part 2 Programming Exercise

• C++ Built-in Operators, Precedence and Associativity

  
  123COM;123COM
  3COM
  C
  O
  2
  2
  

• q2.cpp

  
  #include <iostream>
  #include <string.h>
  using namespace std;
  
  int main(int argc, char **argv){
  	int i,j;
  	for (i = argc - 1; i > 0; i--) {
  		for (j = strlen(argv[i]) - 1; j >= 0; j--) {
  			cout << argv[i][j];
  		}
  		cout << endl;
  	}
  }
  

• q3.cpp

  
  #include <iostream>
  #include <math.h>
  using namespace std ;
  
  int main()
  {
    int num,i;
    bool loopFlag,isPrime;
  
    loopFlag = isPrime = true;
  
    cout << "Please enter a positive integer value: ";
    cin >> num;
  
    if (num == 2)
  	  loopFlag = false;
    else {
  	  if (num % 2 == 0){
  		  isPrime = loopFlag = false;
  	  }
  	  else {
  		  i = 3;
  		  while (loopFlag && (i <= int(sqrt(num)))){
  			  if (num % i == 0){
  				  loopFlag = isPrime = false;
  			  } else i += 2;
  		  }
  	  }
    }
  
    if (isPrime)
  	  cout << num << " is a prime number" << endl;
    else cout << num << " is not a prime number" << endl;
  
    return 0 ;
  }
  
  
  

• q4.py

  
  from StackModule import Stack
  
  stack = Stack()
  print ('Postfix evaluation using Stack')
  postfixExp = input('Enter postfix expression separated by spaces:')
  for e in postfixExp.split():
      if e.isdigit(): 
          stack.push(int(e))
      elif e == '+':
          stack.push(int(str(stack.pop()))+int(str(stack.pop()))) 
      elif e == '*':
          stack.push(int(str(stack.pop()))*int(str(stack.pop())))        
      elif e == '-':
          top = stack.pop()
          stack.push(int(str(stack.pop()))-int(str(top)))
      elif e == '/':
          top = stack.pop()
          stack.push(int(int(str(stack.pop()))/int(str(top))))
  
  print ('The result is:', stack)
  

• Lab 4 q5.py

  
  from StackModule import Stack
  
  def isInt(s):
      try:
          int(s)
          return True
      except ValueError:
          return False
  
  stack = Stack()
  print ('Postfix evaluation using Stack')
  postfixExp = input('Enter postfix expression separated by spaces:')
  for e in postfixExp.split():
      if e.isInt(e): 
          stack.push(int(e))
      elif e == '+':
          stack.push(int(str(stack.pop()))+int(str(stack.pop()))) 
      elif e == '*':
          stack.push(int(str(stack.pop()))*int(str(stack.pop())))        
      elif e == '-':
          top = stack.pop()
          stack.push(int(str(stack.pop()))-int(str(top)))
      elif e == '/':
          top = stack.pop()
          stack.push(int(int(str(stack.pop()))/int(str(top))))
      elif e == '**':
          top = stack.pop()
          stack.push(int(int(str(stack.pop()))**int(str(top))))
  
  print ('The result is:', stack)