Checking for incorrect input?

[Huppa]

How would I check for incorrect input? (ie. if the result is not 1, 2, or -1 to quit. Output = result << " is an incorrect input.";)

      while (result != -1)
      {
      //prompt user for input & obtain val.
         cout << "\nEnter result (1=pass, 2=fail, -1=done): ";
         cin >> result; //input result
      
      //counters
         if (result == 1)
         {
            passed = passed + 1;
            studentCounter++;
         }
      
      
         if (result == 2)
         {
            failures = failures + 1;
            studentCounter++;
         }
      }

[eyenrique]

Hi @Huppa,
this is an
example using
do-while and
while loops i
think that is
the right way;

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//Val_Input.cpp //## #include <iostream> using std::cout; using std::cin; using std::endl; int main(){ int result; do{ cout << "\nEnter result (1=pass, 2=fail, -1=done): "; cin >> result; //input result while(!(result==1||result==2||result==-1)||cin.fail()){ if(cin.fail()){ cin.clear(); cin.ignore(100,'\n'); }//end if cout<<"Invalid input"<<endl; cout<<"Enter result (1=pass, 2=fail, -1=done)"<<endl; cin>>result; }//end while cout<<"result: "<<result<<endl; }while(result!=-1); //end do-while return 0; //indicates success }//end of main

./Val_Input Enter result (1=pass, 2=fail, -1=done): 1 result: 1 Enter result (1=pass, 2=fail, -1=done): 2 result: 2 Enter result (1=pass, 2=fail, -1=done): -2 Invalid input Enter result (1=pass, 2=fail, -1=done) 0 Invalid input Enter result (1=pass, 2=fail, -1=done) 3 Invalid input Enter result (1=pass, 2=fail, -1=done) qwerty Invalid input Enter result (1=pass, 2=fail, -1=done) -1 result: -1