如果语句出现问题，则不会显示正确的输出

我正在尝试制作一个程序，为用户提供从他们想要转换的测量列表中进行选择的选项。
到目前为止，我的代码是：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main()
{
    int sv, SourceUnit, du, mb, kb, by;
    printf("--------------------------------------------------0x0 Menu:------    ---------------------------------\n");
    printf(" Please Select from the following options (enter number exactly when prompted for source units!\n");
    printf("1: Kilo -> Mega\n2: Mega -> Kilo\n10. Bits -> Bytes\n ");
    printf("--------------------------------------------------------------------------------------------------\n");

    printf("Enter source value: ");
    scanf("%d", &sv);

    printf("Enter source unit: ");
    scanf("%s", &SourceUnit);

    if (SourceUnit == 1)                                                            //convert kilobytes to megabytes
    {

        mb = (sv / 1024);
        printf("%d Kb ==  %d Mb\n", sv, mb);
    }

    else if (SourceUnit == 2)                                                           //convert megabytes to kilobytes
    {
        kb = (sv / 1024);
        printf("%d Mb == %d Kb\n", sv, kb);
    }

    else if (SourceUnit == 10)                                                          //bits to bytes
    {
        by = (sv / 8);
        printf("%d Bits == %d Bytes\n", sv, by);
    }

    else 
    {
        printf("Please Choose from the menu options to convert!\n");
    }

    return(0);
}

它在GCC上编译良好。我得到的输出是：

---------------------------------------0x0 Menu:----------------------------
1. Kilo -> Mega
2. Mega -> Kilo
3. Bits -> Bytes
----------------------------------------------------------------------------
Enter Source Value: (Example I will type in 30 for the number to be converted) 30
Enter Source Unit: (Example will be 1 to convert from Kilo to Mega) 1
Please Choose from the menu options to convert! 

由于某种原因，我的else语句在我不希望出现时出现。.什么导致此错误？

我也遇到一些问题，我需要将deka转换为dibi ..究竟该怎么做？我知道deka是10个一组，而dibi是16个一组，但这就是我可以从中读取的所有信息。