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#include <cstdlib>
#include <sstream>
#include <string>
using namespace std;
struct mixedNumber
{
int whole, num, denom;
void output();
};
void mixedNumber::output()
{
if(whole == 0)
if(num == 0)
cout<<0;
else
cout<<num<<"/"<<denom;
else
if(num == 0)
cout<<whole;
else
cout<<whole<<" "<<num<<"/"<<denom;
}
bool input(string &line);
void process(string line);
int gcd(int p, int q);
void reduce(mixedNumber &number);
mixedNumber add(mixedNumber x, mixedNumber y);
mixedNumber mult(mixedNumber x, mixedNumber y);
mixedNumber divide(mixedNumber x, mixedNumber y);
mixedNumber subtract(mixedNumber x, mixedNumber y);
char getOperator(string line, int &pos);
void getOperands(const string &line, mixedNumber &x, mixedNumber &y, int pos);
mixedNumber convertToMixedNumber(string line);
void trim(string &line);
int main()
{
string line;
while(input(line))
process(line);
return 0;
}
bool input(string &line)
{
cout<<"Input: ";
getline(cin,line);
return line != "";
/*
The above is identical, in result, to:
if(line != "")
return true;
else
return false;
which is also the same result of:
return line != "" ? true : false;
*/
}
void getOperands(const string &line, mixedNumber &x, mixedNumber &y, int pos)
{
string first, second;
first = line.substr(0, pos);
second = line.substr(pos+3);
x = convertToMixedNumber(first);
y = convertToMixedNumber(second);
}
void trim(string &line)
{
while(line[0] == ' ')
line.erase(0,1);
}
mixedNumber convertToMixedNumber(string line)
{
stringstream ss;
char junk;
mixedNumber answer;
trim(line);
int pos = line.find(' '),
pos2 = line.find('/');
if(pos < string::npos && pos2 < string::npos) //have a true mixed number!
{
ss << line;
ss>> answer.whole>>answer.num>>junk>>answer.denom;
}
else
if(pos2 >= string::npos)
{
ss<<line;
ss>>answer.whole;
answer.num = 0;
answer.denom = 1;
}
else
{
ss<<line;
ss>>answer.num>>junk>>answer.denom;
answer.whole = 0;
}
return answer;
}
char getOperator(string line, int &pos)
{
string choices[4] = {" + ", " - ", " * ", " / "};
for(int i = 0; i < 4; i++)
if( (pos = line.find(choices[i])) < string::npos)
break;
return pos < string::npos ? line[pos+1] : '\0';
}
void process(string line)
{
mixedNumber one, two, answer;
int pos;
char op = getOperator(line, pos);
if(op == '\0')
{
cout<<"No operator found! Please re-etner"<<endl;
return;
}
getOperands(line, one, two, pos);
switch(op)
{
case '+' : answer = add(one, two);
break;
case '-' : answer = subtract(one,two);
break;
case '*' : answer = mult(one,two);
break;
case '/' : answer = divide(one,two);
}
cout<<line<<" = ";
answer.output();
cout<<endl;
}
int gcd(int p, int q)
{
return q==0 ? p : gcd(q, p%q);
}
void reduce(mixedNumber &number)
{
int newNum = number.denom*number.whole + number.num,
newDenom = number.denom,
divisor = gcd(newNum,newDenom );
newNum /= divisor;
newDenom /= divisor;
number.whole = newNum/newDenom;
number.num = newNum %newDenom;
number.denom = newDenom;
}
mixedNumber add(mixedNumber x, mixedNumber y)
{
mixedNumber answer;
answer.whole = 0;
answer.num = y.denom*(x.denom*x.whole + x.num) + x.denom*(y.denom*y.whole + y.num);
answer.denom = x.denom * y.denom;
reduce(answer);
return answer;
}
mixedNumber mult(mixedNumber x, mixedNumber y)
{
mixedNumber answer;
answer.whole = 0;
answer.num = (x.denom*x.whole + x.num) * (y.denom*y.whole + y.num);
answer.denom = x.denom * y.denom;
reduce(answer);
return answer;
}
mixedNumber divide(mixedNumber x, mixedNumber y)
{
mixedNumber answer;
answer.whole = 0;
answer.num = (x.denom*x.whole + x.num) * y.denom ;
answer.denom = x.denom * (y.denom*y.whole + y.num);
reduce(answer);
return answer;
}
mixedNumber subtract(mixedNumber x, mixedNumber y)
{
mixedNumber answer;
answer.whole = 0;
answer.num = y.denom*(x.denom*x.whole - x.num) + x.denom*(y.denom*y.whole + y.num);
answer.denom = x.denom * y.denom;
reduce(answer);
return answer;
}
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