Functions in C are ALWAYS:

Global variables are:

Which of the following are an external variable?
    int func (int a)
    {
        int b;
        return b;
    }
    int main()
    {
        int c;
        func (c);
    }
    int d;

What will be the output?
    int main()
    {
        printf("%d", d++);
    }
    int d = 10;

What will be the output?
    double var = 8;
    int main()
    {
        int var = 5;
        printf("%d", var);
    }

What is the output of this C code?
    double i;
    int main()
    {
       printf("%g\n",i);
       return 0;
    }

Which part of the program address space is p stored in the code given below?
    int *p = NULL;
    int main()
    {
        int i = 0;
        p = &i;
        return 0;
    }

Which part of the program address space is p stored in the code given below?
    int *p;
    int main()
    {
        int i = 0;
        p = &i;
        return 0;
    }

Can variable i be accessed by functions in another source file?
    int i;
    int main()
    {
        printf("%d\n", i);
    }

Property of external variable to be accessed by any source file is called by C90 standard as:

What is the output of this C code?
    int *i;
    int main()
    {
        if (i == NULL)
            printf("true\n");
        return 0;
    }

What is the output of this C code?
    int *i;
    int main()
    {
        if (i == 0)
            printf("true\n");
        return 0;
    }

What is the output of this C code?
    static int x = 5;
    void main()
    {
        x = 9;
        {
            int x = 4;
        }
        printf("%d", x);
    }