Base Conversion

EPI 7.2

Description:

number as string, convert from base b1 to base b2

Example:

Note

Idea:

1. Convert to integer number
2. Convert from integer number to string

Code:

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cctype>

using namespace std;

string intToString(int num, int b){
    bool isNegative= num<0;
    num=abs(num);
    string result;

    while(num){
        int digit = num%b;
        result.push_back(digit>=10? digit-10+'A': digit+'0');
        num=num/b;
    }
    if(isNegative)
        result += '-';

    return string(result.rbegin(), result.rend());
}

string baseConversion(string num, int b1, int b2){
    int numInt=0;
    bool isNegative= num[0] =='-';
    for(int i=isNegative?1:0 ; i<num.size(); i++ ){
        int digit= isdigit(num[i])? num[i]-'0': num[i]-'A'+10;
        numInt = numInt*b1 + digit;
    }
    return intToString(numInt, b2);
}

int main(){
    cout<<baseConversion("102", 3, 4);
}