Any Base Conversion

C++ implementation of Any Base to Any Base Conversion.

#include <cstdio>
#include <vector>
#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

#define all(x) x.begin(),x.end()

template<class t> inline t power(t num,t p)
{
    if(!p)    return 1;return (num*power(num,p-1));
}

bool islow(char ch){if(ch>='a' && ch<='z') return true; return false;}
bool isupp(char ch){if(ch>='A' && ch<='Z') return true; return false;}
bool isdig(char ch){if(ch>='0' && ch<='9') return true; return false;}

//any base to decimal conversion
int todec(string s,int base)
{
    int i,j,temp,len,sum=0;

    len=s.length()-1;
    for(i=0,j=len;i<=len;i++,j--)
    {
        char ch=s.at(i);
        if(isdig(ch))         temp=ch-'0';
        else if(islow(ch))    temp=10+ch-'a';
        else if(isupp(ch))    temp=10+ch-'A';

        sum+=(temp*(power(base,j)));
    }

    return sum;
}


//decimal to any base conversion
string tobase(int num,int base)
{
    int temp;
    string s;
    char ch;
    if(!num)    return "0"; //special '0' case handling

    while(num>0)
    {
        temp=num%base;
        num/=base;
        if(temp<=9) s+=(temp+'0');
        else        s+=((temp-10)+'A');
    }
    reverse(all(s));
    return s;
}