C++でのゼロ除算例外の処理

このチュートリアルでは、C++でゼロ除算例外を処理する方法について説明します。

ゼロ除算は数学では未定義のエンティティであり、ユーザー側でエラーが返されないように、プログラミング中に適切に処理する必要があります。

runtime_errorクラスの使用

例

#include <iostream>
#include <stdexcept>
using namespace std;
//handling divide by zero
float Division(float num, float den){
   if (den == 0) {
      throw runtime_error("Math error: Attempted to divide by Zero\n");
   }
   return (num / den);
}
int main(){
   float numerator, denominator, result;
   numerator = 12.5;
   denominator = 0;
   try {
      result = Division(numerator, denominator);
      cout << "The quotient is " << result << endl;
   }
   catch (runtime_error& e) {
      cout << "Exception occurred" << endl << e.what();
   }
}

出力

Exception occurred
Math error: Attempted to divide by Zero

ユーザー定義の例外処理の使用

例

#include <iostream>
#include <stdexcept>
using namespace std;
//user defined class for handling exception
class Exception : public runtime_error {
   public:
   Exception()
   : runtime_error("Math error: Attempted to divide by Zero\n") {
   }
};
float Division(float num, float den){
   if (den == 0)
   throw Exception();
   return (num / den);

}
int main(){
   float numerator, denominator, result;
   numerator = 12.5;
   denominator = 0;
   //trying block calls the Division function
   try {
      result = Division(numerator, denominator);
      cout << "The quotient is " << result << endl;
   }
   catch (Exception& e) {
      cout << "Exception occurred" << endl << e.what();
   }
}

出力

Exception occurred
Math error: Attempted to divide by Zero

スタック巻き戻しの使用

例

#include <iostream>
#include <stdexcept>
using namespace std;
//defining function to handle exception
float CheckDenominator(float den){
   if (den == 0) {
      throw runtime_error("Math error: Attempted to divide by zero\n");
   }
   else
      return den;
}
float Division(float num, float den){
   return (num / CheckDenominator(den));
}
int main(){
   float numerator, denominator, result;
   numerator = 12.5;
   denominator = 0;
   try {
      result = Division(numerator, denominator);
      cout << "The quotient is " << result << endl;
   }
   catch (runtime_error& e) {
      cout << "Exception occurred" << endl << e.what();
   }
}

出力

Exception occurred
Math error: Attempted to divide by Zero