Monday 24 December 2012

C/C++ Puzzles: PART - 3


Static Variables are Initialized at Compile Time

Consider the Two programs given below.

//Program 1
#include<stdio.h>
int aaa=10;
int main()
{
    static int bbb=aaa;
    printf("Value is %d\n",bbb);
    return 0;
}

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//Program 2
#include<stdio.h>
const int aaa=10;
int main()
{
    static int bbb=aaa;
    printf("Value is %d\n",bbb);
    return 0;
}


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Both the programs will give you the following error message on Code::Blocks 10.05, "Initializer element is not constant". Reason? Static variables are initialized at compile time. So either it should be initialized with a constant value or leave the initialization to the compiler, which will initialize the static variable to zero.

The program given below corrects the error.

#include<stdio.h>
#define aaa 10
int main()
{
    static int bbb=aaa;
    printf("Value is %d\n",bbb);
    return 0;
}

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The program below declares bbb as an automatic variable and there are no errors. Remember the default storage class is automatic (auto).

#include<stdio.h>
int aaa=10;
int main()
{
    int bbb=aaa;
    printf("Value is %d\n",bbb);
    return 0;
}

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