Question

I designed a C++ code for checking machine’s endian.
It works well. But, it cannot print out each bytes’ contents in a 4-byte int.

#include<iostream>
using namespace std;
bool f()
{
    int a = 1;
    char *p = (char*)&a;
    for (int i = 0 ; i < 4 ; ++i)
            cout << "p[" << i << "] is " << hex << *p++ << "   ";
    cout << endl ;
    p -= 4;
    if (*p == 1) return true ; // it is little endian
    else return false;  // it is big endian
}

int main()
{
    cout << "it is little endian ? " << f() << endl ;
    return 0 ;
}

output:

 p[0] is    p[1] is    p[2] is    p[3] is
 it is little endian ? 1

Why the output is empty ?

thanks

Answer 1

the issue is that the type of *p is char, so the stream attempts to print the value of it as an ASCII character (which is likely not the value of a visible character). If you cast it to an int you will get what you expect:

cout << "p[" << i << "] is " << hex << static_cast<int>(*p++) << "   ";