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#include <iostream.h> #include <stdlib.h> #include <math.h> class CFraction { private: long num; long den; public: CFraction(int num_val = 0, int den_val = 1); CFraction &add(const CFraction &r_f); CFraction &sub(const CFraction &r_f); CFraction &mul(const CFraction &r_f); CFraction &div(const CFraction &r_f); void lowTerms(); void showFraction(); }; CFraction::CFraction(int num_val, int den_val) { num = num_val; den = den_val; } CFraction & CFraction::add(const CFraction &r_f) { num = num*r_f.den + den*r_f.num; den = den*r_f.den; lowTerms(); return *this; } CFraction &CFraction::sub(const CFraction &r_f) { num = num*r_f.den - den*r_f.num; den = den*r_f.den; lowTerms(); return *this; } CFraction &CFraction::mul(const CFraction &r_f) { num = num*r_f.num; den = den*r_f.den; lowTerms(); return *this; } CFraction &CFraction::div(const CFraction &r_f) { num = num*r_f.den; den = den*r_f.num; lowTerms(); return *this; } void CFraction::showFraction() { long fz, fm; fz = num; fm = den; if (fz*fm < 0) { cout << "-"; if (fz < 0) fz *= -1; if (fm < 0) fm *= -1; } cout << fz << "/" << fm << endl; } void CFraction::lowTerms() { long tnum, tden, temp, gcd; tnum = labs(num); tden = labs(den); if (tnum != 0 && tden == 0) //check for n/0 { cout << "Illegal fraction: division by 0"; exit(1); } else if (tnum == 0) { num = 0; den = 1; return; } while (tnum != 0) //找分子和分母的最大公约数 { if (tnum < tden) //若分子大于分母，则交换 { temp = tnum; tnum = tden; tden = temp; } tnum = tnum - tden; } gcd = tden; num = num / gcd; den = den / gcd; } void main() { CFraction fs1(2, 3), fs2(1, 2); fs1.add(fs2); fs1.showFraction(); fs1.sub(fs2); fs1.showFraction(); }