Declaring and Initializing C++ Static variables

Question

Note: This is coming from a beginner.

Why does the first one outputs 333 and the second one 345 ?

In the second code does it skips over the declaration? I mean it should initialise the "j" variable again like in the first one.

int main() {
    static int j =12;
    for(int i=0; i<=2; i++) {
        j = 2;
        j += 1;
        std::cout<<j;
    }
    return 0;
}

int main() {
    
    for(int i=0; i<=2; i++) {
        static int j = 2;
        j += 1;
        std::cout<<j;
    }
    return 0;
}

First question: What's your understanding of what static variables are? — tadman
– tadman, Commented Mar 28, 2021 at 18:22

DeltA · Accepted Answer · 2021-03-28 18:26:21Z

2

static variables are only initialized once (when first used). After that, it behaves as if it is declared somewhere else (I mean, the initialization is ignored). In the second main, the initialization static int j = 2; is executed only the first time, after that, you are incrementing it sequentially (i.e. 2,3,4...) In the first loop, you set it's value on each iteration, which is not the same as initialization, so it can be run multiple times.

answered Mar 28, 2021 at 18:26

DeltA

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