Interesting facts about data-types and modifiers in C/C++

• Difficulty Level : Easy
• Last Updated : 17 Apr, 2020

Here are some logical and interesting facts about data-types and the modifiers associated with data-types:-

1. If no data type is given to a variable, the compiler automatically converts it to int data type.

• C++
• C

#include <iostream>

using namespace std;

int main()

{

    signed a;

    signed b;

    // size of a and b is equal to the size of int

    cout << "The size of a is " << sizeof(a) <<endl; 

    cout << "The size of b is " << sizeof(b); 

    return (0);

}

// This code is contributed by shubhamsingh10

Output:

The size of a is 4The size of b is 4

2. Signed is the default modifier for char and int data types.

• C++
• C

#include <iostream>

using namespace std;

int main()

{

    int x;

    char y;

    x = -1;

    y = -2;

    cout << "x is "<< x <<" and y is " << y << endl;

}

// This code is contributed by shubhamsingh10

Output:

x is -1 and y is -2.

3. We can’t use any modifiers in float data type. If programmer tries to use it ,the compiler automatically gives compile time error.

• C++
• C

#include <iostream>

using namespace std;

int main()

{

    signed float a;

    short float b;

    return (0);

}

//This article is contributed by shivanisinghss2110

Output:

[Error] both 'signed' and 'float' in declaration specifiers[Error] both 'short' and 'float' in declaration specifiers

4. Only long modifier is allowed in double data types. We cant use any other specifier with double data type. If we try any other specifier, compiler will give compile time error.

• C++
• C

#include <iostream>

using namespace std;

int main()

{

    long double a;

    return (0);

}

// This code is contributed by shubhamsingh10

• C++
• C

#include <iostream>

using namespace std;

int main()

{

    short double a;

    signed double b;

    return (0);

}

// This code is contributed by shubhamsingh10

Output:

[Error] both 'short' and 'double' in declaration specifiers[Error] both 'signed' and 'double' in declaration specifiers