How can I redefine variables in C?

Question

#include <stdio.h>
int main(void)
{
    int i = 365, j = 100, result = i + j;

    printf("i + j is %i\n", result);

    int i = 100, j = 1;
    printf("i + j is %i\n", result);

    return 0;
}

9.c:10:10: error: declaration shadows a local variable [-Werror,-Wshadow] 9.c:8:9: error: redefinition of 'i'

I've reformatted and tagged as C since you're using <stdio.h>. Do retag if it's C++. — Bathsheba
– Bathsheba, Commented Nov 30, 2016 at 15:34
" redefinition of 'i'" Well... look at the code. Why do you think it doesn't work? — Lundin
– Lundin, Commented Nov 30, 2016 at 16:28

Bathsheba · Accepted Answer · 2016-11-30 15:37:23Z

8

Replace int i = 100 with i = 100.

You are not allowed to redeclare a variable in the same scope in C and C++. But you can set i to a different value, which is what my change does.

Finally, if you want the final output of result to be the sum of the new values of i and j, then you have to recompute. Put result = i + j; just before the printf call.

edited Nov 30, 2016 at 15:37

answered Nov 30, 2016 at 15:33

Bathsheba

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2 Comments

Yellowfun Over a year ago

Output is i + j is 465 i + j is 465

Bathsheba Over a year ago

That's because you don't re-evalute result after changing i and j. I've amended the answer.

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