ConvertFileSize

#include <stdio.h>
#include <windows.h>

unsigned long long ConvertFileSize(unsigned long long iBytes, char *i10);

/* тест функции power */
int main()
{
    unsigned long long z;
    // char i10[3] = " B";
    char i10[3] = {' ', 'B', '\0'};
    z = ConvertFileSize(1025, &i10);
    printf("%d  -  %s\n", z, i10);
    //system("pause");
    return 0;
}

unsigned long long ConvertFileSize(unsigned long long iBytes, char *i10)
{
    const unsigned long long iConst = 0.0000234375; // (1024 / 1000 - 1) / 1024
    if ((iBytes >= 110154232090684)&&(iBytes <= 1125323453007766)) // TB
        {iBytes = iBytes / (1099511627776 + iBytes * iConst);
        iBytes = round(iBytes);
        *i10 = "TB";}
    else if ((iBytes >= 1098948684577)&&(iBytes <= 110154232090683)) // TB
        {iBytes = iBytes *10 / (1099511627776 + iBytes * iConst);
        iBytes = round(iBytes) / 10;
        *i10 = "TB";}
    else if ((iBytes >= 107572492277)&&(iBytes <= 1098948684576)) // GB
        {iBytes = iBytes / (1073741824 + iBytes * iConst);
        iBytes = round(iBytes);
        *i10 = "GB";}
    else if ((iBytes >= 1073192075)&&(iBytes <= 107572492276)) // GB
        {iBytes = iBytes *10 / (1073741824 + iBytes * iConst);
        iBytes = round(iBytes) / 10;
        *i10 = "GB";}
    else if ((iBytes >= 105156613)&&(iBytes <= 1073192074)) // MB
        {iBytes = iBytes / (1048576 + iBytes * iConst);
        iBytes = round(iBytes);
        *i10 = "MB";}
    else if ((iBytes >= 1048040)&&(iBytes <= 105156612)) // MB
        {iBytes = iBytes *10 / (1048576 + iBytes * iConst);
        iBytes = round(iBytes) / 10;
        *i10 = "MB";}
    else if ((iBytes >= 102693)&&(iBytes <= 1048039)) // KB
        {iBytes = iBytes / (1024 + iBytes * iConst);
        iBytes = round(iBytes);
        *i10 = "KB";}
    else if ((iBytes >= 1000)&&(iBytes <= 102692)) // KB
        {iBytes = iBytes *10 / (1024 + iBytes * iConst);
        iBytes = round(iBytes) / 10;
        *i10 = 'K';}
    return iBytes;
}