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c++memset

memset sets random values

Here is the code:

#include <iostream>
#include <cstring>

int main()
{
    int win[11];
    std::memset(win, 1, sizeof(win));
    for (int i = 0; i < 11; ++i)
        std::cout << win[i] << ' ';
    std::cout << std::endl;

    return 0;
}

I think there is no logic flaw here? But instead of getting a string of 1 printed, I got 16843009.

If I change the memset to std::memset(win, 0, sizeof(win)). Then everything is as expected. The content of win is all zeros.

Am I missing something here?

I'm using g++ 4.7.3 on Ubuntu 13.04.

Sorry for this duplicated question.

Here is the answer. Thanks

Why does "memset(arr, -1, sizeof(arr)/sizeof(int))" not clear an integer array to -1?

Solution

  • ints are usually four bytes long. But memset sets the value of individual bytes, so you're setting each value to 0x01010101, which just so happens to equal 16843009.