java - Scanner is skipping nextLine() after using next(), nextInt() or other nextFoo()? -


i using scanner methods nextint() , nextline() reading input. basically, looks this:

system.out.println("enter numerical value");     int option; option = input.nextint();//read numerical value input system.out.println("enter 1st string");  string string1 = input.nextline();//read 1st string (this skipped) system.out.println("enter 2nd string"); string string2 = input.nextline();//read 2nd string (this appears right after reading numerical value) 

the problem after entering numerical value, first input.nextline() skipped , second input.nextline() executed, output looks this:

enter numerical value 3   //this input enter 1st string    //the program supposed stop here , wait input, skipped enter 2nd string    //and line executed , waits input 

i tested application , looks problem lies in using input.nextint(). if delete it, both string1 = input.nextline() , string2 = input.nextline() executed want them be.

that's because scanner.nextint method not consume last newline character of input, , newline consumed in next call scanner.nextline.

workaround:

  • either fire blank scanner.nextline call after scanner.nextint consume rest of line including newline

    int option = input.nextint(); input.nextline();  // consume newline left-over string str1 = input.nextline(); 
  • or, better, if read input through scanner.nextline , convert input integer using integer.parseint(string) method.

    int option = 0; try {     option = integer.parseint(input.nextline()); } catch (numberformatexception e) {     e.printstacktrace(); } string str1 = input.nextline(); 

you encounter similar behaviour when use scanner.nextline after scanner.next() or scanner.nextfoo method (except nextline itself).


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