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why the calculator is not working properly ?

+5 votes
asked Nov 27, 2021 by CPradhe (170 points)
#include <iostream>

using namespace std;

int

main ()

{

  char op;

  int a, b, c, d;

  cout << "if you are want to open calcutor then enter 1" << endl

    << "if you are want to find maximum number out of three then enter 2" <<

    endl << "if you are want to find odd-even then enter 3" << endl;

  cin >> d;

  switch (d)

    {

    case 1:

      cout << "entar first number" << endl;

      cin >> a;

      cout << "entar second number" << endl;

      cin >> b;

      cout << "enter the operation( +,-,*,/)" << endl;

      cin >> op;

      if (op = '/')

{

  cout << a << "/" << b << "=" << (float) a / b << endl;

}

      else if (op = '-')

{

  cout << a << "-" << b << "=" << a - b << endl;

}

      else if (op = '*')

{

  cout << a << "*" << b << "=" << a * b << endl;

}

      else if (op = '+')

{

  cout << a << "+" << b << "=" << a + b << endl;

}

      break;

    case 2:

      cout << "enter three number one by one" << endl;

      cin >> a >> b >> c;

      if (a > b)

{

  if (a > c)

    {

      cout << "maximum number is\t" << a << endl;

    }

  else

    {

      cout << "maximum number is\t" << c << endl;

    }

}

      else if (b > a)

{

  if (b > c)

    {

      cout << "maximum number is\t" << b << endl;

    }

  else

    {

      cout << "maximum number is\t" << c << endl;

    }

}

      break;

    case 3:

      cout << "enter any number" << endl;

      cin >> a;

      if (a % 2 == 0)

{

  cout << a << "\tis an even number" << endl;

}

      else

{

  cout << a << "\tis an odd number" << endl;

}

      break;

    default:

      cout << "invalid number";

    }

}

1 Answer

+1 vote
answered Nov 28, 2021 by Peter Minarik (55,660 points)

Assignment vs equality check

The = operator is the assignment operator. It assigns value to a variable. E.g.:

op = '/'

The == operator is the equality check operator. It checks if the left side and the right side are equal. E.g.

op == '/'

Also, before your finish your main function, you should set the return value as it has an int return type:

return 0;
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