在两个 if 语句中使用 Java 中的变量

Question

所以我目前正在编写一个程序，要求用户提供他们将乘以的多项式的次数，然后再乘以所述多项式。我的程序设置为只乘以三次多项式。我使用 if 语句来检查次数，然后提示用户输入所需的系数数。但是，我在程序中还有另一个 if 语句，它使用这些系数并将它们分配给乘积多项式的系数。它说我不能使用这个变量，因为它可能还没有被初始化？？我在代码的开头声明了所有变量，而不是在 if 语句中，但它仍然说它可能尚未初始化。我将在下面包含代码。如有任何帮助，我们将不胜感激！

           if (degreeform == 1)
              {
                 degreeformstate = true;
                 
                 coef_A = conIO.promptForInt("Enter coefficient a: ");
                 conIO.printEndline();
                 
                 coef_B = conIO.promptForInt("Enter coefficient b: ");
                 conIO.printEndline();
                 
                 coef_C = conIO.promptForInt("Enter coefficient c: ");
                 conIO.printEndline();
                 
                 coef_D = conIO.promptForInt("Enter coefficient d: ");
                 conIO.printEndlines(TWO_ENDLINES);
              }
           
           else if (degreeform == 2)
              {
                 degreeformstate = true;
                 
                 coef_A = conIO.promptForInt("Enter coefficient a: ");
                 conIO.printEndline();
                 
                 coef_B = conIO.promptForInt("Enter coefficient b: ");
                 conIO.printEndline();
                 
                 coef_C = conIO.promptForInt("Enter coefficient c: ");
                 conIO.printEndline();
                 
                 coef_D = conIO.promptForInt("Enter coefficient d: ");
                 conIO.printEndline();
                 
                 coef_E = conIO.promptForInt("Enter coefficient e: ");
                 conIO.printEndlines(TWO_ENDLINES);
              }
           
           else if (degreeform == 3)
              {
                 degreeformstate = true;
                 
                 coef_A = conIO.promptForInt("Enter coefficient a: ");
                 conIO.printEndline();
                 
                 coef_B = conIO.promptForInt("Enter coefficient b: ");
                 conIO.printEndline();
                 
                 coef_C = conIO.promptForInt("Enter coefficient c: ");
                 conIO.printEndline();
                 
                 coef_D = conIO.promptForInt("Enter coefficient d: ");
                 conIO.printEndline();
                 
                 coef_E = conIO.promptForInt("Enter coefficient e: ");
                 conIO.printEndline();
                 
                 coef_F = conIO.promptForInt("Enter coefficient f: ");
                 conIO.printEndlines(TWO_ENDLINES);
              }

           else 
              {
                 degreeformstate = false;
                 
                 conIO.printString("Incorrect number of polynomial degrees entered - Program Aborted");
                 System.exit(0);
              
              }

              if (degreeform == 1)
                 {
                    coef_V = coef_A * coef_C;
                    coef_W = (coef_B * coef_C) + (coef_A * coef_D);
                    coef_X = (coef_B * coef_D);
                 }
                 
              // polynomial type 2
              else if (degreeform == 2)
                 {
                    coef_V = coef_A * coef_C;
                    coef_W = (coef_B * coef_C) + (coef_A * coef_D);
                    coef_X = (coef_A * coef_E) + (coef_B * coef_D);
                    coef_Y = coef_B * coef_E;
                 }
              // polynomial type 3
              else 
                 {
                    coef_V = coef_A * coef_C;
                    coef_W = (coef_B * coef_C) + (coef_A * coef_D);
                    coef_X = (coef_A * coef_E) + (coef_B * coef_D);
                    coef_Y = (coef_A * coef_F)+ (coef_B * coef_E);
                    coef_Z = coef_B * coef_E;
                 }

Answer 1

您不必声明，而是在代码开头或 else 块中将变量初始化为其默认值。

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