Question

3. Write a C program to check if an input integer is a multiple of either 2 or 5 but not a multiple of both. E.g. of valid numbers are 4, 6, 8, 12, 14, 15, 16, 25, etc. E.g. of invalid numbers are 1, 3, 7, 9, 10, 20, etc. 4. Write a C program to check whether an input number is a multiple of only 5( e.g. 5,10,15,…), only 11 (e.g. 11,22,33,… ), both 5 and 11 (e.g. 55,110,… ), or neither of them (e.g. 2,3,4,6,7,8,9,12,… ).

Answer 1

#include <stdbool.h>

#include <stdio.h>

bool two_or_five(int n)

char *five_eleven(int n)

{

bool five = n % 5 == 0;

bool eleven = n % 11 == 0;

if (five && !eleven)

{

return "five";

}

else if (eleven && !five)

{

return "eleven";

}

else if (five && eleven)

{

return "five and eleven";

}

else if (!five && !eleven)

{

return "neither five nor eleven";

}

else

{

return "";

}

}

int main()

{

int n = 2;

printf("%s\\", two_or_five(n) ? "true" : "false");

printf("%d is a multiple of %s", n, five_eleven(n));

return 0;

}

(Note that bool is not a type that is available by default in C, so we have to import it using the header file)