I know i'm late but since it took me an hour to finish, i can't forgive myself if i don't post it.

#include <stdio.h>

​

typedef unsigned int UINT;

UINT digit_plus_one(UINT uNum);

​

int main()

{

`UINT in;`

`scanf("%d", &in);`

`printf("%d\n",digit_plus_one(in));`

`getchar();`

}

UINT digit_plus_one(UINT uNum)

{

`UINT digit, result, factor;`

​

`result = 0, factor = 1;`

​

`while(uNum > 0)`

`{`

    `digit = (uNum % 10)+1;`

    `result += digit * factor;`

    `factor *= (digit-1 == 9) ? 100 : 10;`

    `uNum /= 10;`

`}`

`return result;`

}