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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++




#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

C




#include <stdio.h>
int main()
{
    signed a;
    signed b;
  
    // size of a and b is equal to the size of int
    printf("The size of a is %d\n", sizeof(a)); 
    printf("The size of b is %d", sizeof(b)); 
    return (0);
}


Output:
The size of a is 4
The size of b is 4

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

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

C




#include <stdio.h>
int main()
{
    int x;
    char y;
    x = -1;
    y = -2;
    printf("x is %d and y is %d", x, y);
}


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++




#include <iostream>
using namespace std;
int main()
{
    signed float a;
    short float b;
    return (0);
}
//This article is contributed by shivanisinghss2110

C




#include <stdio.h>
int main()
{
    signed float a;
    short float b;
    return (0);
}


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++




#include <iostream>
using namespace std;
int main()
{
    long double a;
    return (0);
}
  
// This code is contributed by shubhamsingh10

C




#include <stdio.h>
int main()
{
    long double a;
    return (0);
}

C++




#include <iostream>
using namespace std;
int main()
{
    short double a;
    signed double b;
    return (0);
}
  
// This code is contributed by shubhamsingh10

C




#include <stdio.h>
int main()
{
    short double a;
    signed double b;
    return (0);
}


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

This article is contributed by Bishal Kumar Dubey. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.

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