Why does determining the max value returning the wrong value with if-else condition ?

You may also write:

int max( int a, int b, int c, int d)
{
  return a > b ? ( a > c ? ( a > d ? a : d) : ( c > d ? c : d) ) : ( b > c ? ( b > d ? b : d ) : (c > d ? c : d));
}

At the time of this writing, here is what your code looks like :

int max (int a, int b, int c, int d){   
    int result = a;
    result > b ? result : result = b;
    result > c ? result : result = c;
    result > d ? result : result = d;
    return result; 
}

Those ternary expressions still don't look right. They should be of the form:

result = ( result > b ) ? result : b;

Also, naming a c++ function max is not a good idea. There is a macro named max in the standard C headers and the Standard Template Library has a template function named max. It would better to use a different name for this function. I prefer to use a function that assigns the result to a value that is passed in. Here's an example :

__inline void AssignMax( int & maxvalue, int newvalue )
{
    if( maxvalue < newvalue )
        maxvalue = newvalue;
}

and then you can rewrite your function like this :

int GetMaxValue( int a, int b, int c, int d )
{
    result = a;
    AssignMax( result, b );
    AssignMax( result, c );
    AssignMax( result, d );
    return result;
};

One advantage to this approach is it does not constantly assign the value to result. It only does so when the argument passed is larger than it.

Your problem:

<pre>int max (int a, int b, int c, int d){
    int result = a;
    if (result > b) return result; else result = b; // if a>b you return the answer directly without checking c and d 
    if (result > c) return result; else result = c;
    if (result > d) return result; else result = d;
    return result; 
}
 
INPUT : 6 4 2 13
OUTPUT: 6

Quote:

I just need help to understand why my first trial with if-else condition wouldn't work correctly.

Your code do not behave the way you expect, or you don't understand why !

There is an almost universal solution: Run your code on debugger step by step, inspect variables.
The debugger is here to show you what your code is doing and your task is to compare with what it should do.
There is no magic in the debugger, it don't know what your code is supposed to do, it don't find bugs, it just help you to by showing you what is going on. When the code don't do what is expected, you are close to a bug.
To see what your code is doing: Just set a breakpoint and see your code performing, the debugger allow you to execute lines 1 by 1 and to inspect variables as it execute.

Debugger - Wikipedia, the free encyclopedia[^]

Mastering Debugging in Visual Studio 2010 - A Beginner's Guide[^]
Basic Debugging with Visual Studio 2010 - YouTube[^]

1.11 — Debugging your program (stepping and breakpoints) | Learn C++[^]

The debugger is here to only show you what your code is doing and your task is to compare with what it should do.

Greetings Kind Regards For you to solve the problem may I suggest learning the meaning and behavior of return - Cheerio