[問題] a question about ==

[jasonfly07 (kanata)]

in a simple programm for addition as follows:

#include <iostream>
using namespace std;

int main()

{
    int x, y, sum;

    cout << "Input the first integer: ";
    cin >> x;

    cout << "Input the second integer: ";
    cin >> y;

    sum == x + y;

    cout << "The sum is: " << sum << endl;

    system ("pause");
    return 0;
}

what I've midified is swaping the "=" for "=="
I know their difference-- just want to see what will happen,
and whichever two numbers i give to it, the "sum" is always a specific number:
2294360

any explanation, please?

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推 ric2k1:Basically this line "sum == x+y" just do the comparison
推 ric2k1:without affecting the value of sum.
→ ric2k1:the value of sum is basically the uninitialized value
→ ric2k1:in the line "int x, y, sum".
→ ric2k1:You can try to initialize sum by, say "int sum = 38"
推 ric2k1:and you should see sum is = 38.
→ ric2k1:Actually please turn on "-Wall" and you will see the
→ ric2k1:warning message "sum is used without initialization"
推 cg12037:那如果要計算sum 要怎麼做?