如何编写此程序

#include <stdio.h>

int main( void )
{
    for( unsigned abc=0; abc<1000; ++abc )
    {
        unsigned cba = abc/1%10*100
                     + abc/10%10*10
                     + abc/100%10*1;
        if( abc+cba == 1333 )
            printf( "%03u\n", abc );
    }
}

#include <stdio.h>

int main( void )
{
    for( unsigned a=0; a!=10; ++a )
        for( unsigned b=0; b!=10; ++b )
            for( unsigned c=0; c!=10; ++c )
                if( (c+a)*1+(b+b)*10+(a+c)*100 == 1333 )
                    printf( "%u%u%u\n", a, b, c );
}