Convert from decimal to base-n number system and vice versa

Convert from decimal to base-n number system
We can implement this with a simple, easy to understand program:

void g( int x, int n ) {
    if ( x ) {
        g( x / n, n );
        std::cout << x % n;
    }
}

Convert from decimal to base-n number system
Let’s  consider an example converting a binary number to decimal number:

We also can write it like this:

Expanding for base-n number system, if we have a number in base-n number system:
Then:

Finally we have a program without the need of pow function:

int h( char * src, int n ) {
    int decimal = 0;
    for( char * p = src; p - src < strlen( src ); p++ ) {
        decimal = decimal * n + *p - '0';
    }

    return decimal;
}