# Program to show decimal number from rational number representation in C++

C++Server Side ProgrammingProgramming

Suppose we have two numbers called numerator and denominator representing a rational number in the form (numerator / denominator). We have to find its decimal representation as a string. If there are some recurring numbers, then surround them with brackets.

So, if the input is like numerator = 164 denominator = 3, then the output will be "54.(6)".

To solve this, we will follow these steps −

• if numerator is same as 0, then −
• return "0"
• Define an array ans
• if numerator < 0 and denominator > 0 or numerator > 0 and denominator < 0, then −
• insert '-' at the end of ans
• divisor := |numerator|
• dividend := |denominator|
• remainder := divisor mod dividend
• x := convert (divisor / dividend) to string
• for initialize i := 0, when i < size of x, update (increase i by 1), do −
• insert x[i] at the end of ans
• if remainder is same as 0, then −
• return ans as string
• insert '.' at the end of ans
• Define one map m
• while remainder is not equal to 0, do −
• if remainder is not in m, then −
• insert (first element of ans concatenate '(') into ans
• insert ')' at the end of ans
• Come out from the loop
• Otherwise −
• m[remainder] := size of ans
• remainder := remainder * 10
• insert (remainder / dividend) concatenate '0' at the end of ans
• remainder := remainder mod dividend
• return ans as string

## Example

Let us see the following implementation to get better understanding −

Live Demo

#include <bits/stdc++.h>
using namespace std;
class Solution {
public:
string solve(int numerator, int denominator) {
if (numerator == 0)
return "0";
vector<char> ans;
if (numerator < 0 && denominator > 0 || numerator > 0 && denominator < 0)
ans.push_back('-');
long divisor = labs(numerator);
long dividend = labs(denominator);
long remainder = divisor % dividend;
string x = to_string(divisor / dividend);
for (int i = 0; i < x.size(); i++) {
ans.push_back(x[i]);
}
if (remainder == 0) {
return string(ans.begin(), ans.end());
}
ans.push_back('.');
map<int, int> m;
while (remainder != 0) {
if (m.find(remainder) != m.end()) {
ans.insert(ans.begin() + m[remainder], '(');
ans.push_back(')');
break;
} else {
m[remainder] = ans.size();
remainder *= 10;
ans.push_back((remainder / dividend) + '0');
remainder %= dividend;
}
}
return string(ans.begin(), ans.end());
}
};
string solve(int numerator, int denominator) {
return (new Solution())->solve(numerator, denominator);
}
int main() {
cout << solve(164, 3);
}

## Input

164, 3

## Output

54.(6)
Published on 12-Dec-2020 08:54:06