我需要帮助这是java中g.p.a计算器的代码，但它一直给我错误的变量未初始化...我不知道问题是什么。 （源代码：http://pastebin.com/m6q0zpD4）
import javax.swing.JOptionPane;
public class coursework_1 {
public static void main(String args[]) {
String Course1;
String Course2;
String Course3;
String Course4;
String Course5;
String Course6;
String Course7;
String Course8;
String Course9;
String courseUnit1, courseUnit2, courseUnit3, courseUnit4, courseUnit5, courseUnit6, courseUnit7, courseUnit8, courseUnit9;
int c1, c2, c3, c4, c5, c6, c7, c8, c9;
int creditUnit1, creditUnit2, creditUnit3, creditUnit4, creditUnit5, creditUnit6, creditUnit7, creditUnit8, creditUnit9;
int Course1Val, Course2Val, Course3Val, Course4Val, Course5Val, Course6Val, Course7Val, Course8Val, Course9Val;
String cG1, cG2, cG3, cG4, cG5, cG6, cG7, cG8, cG9;
char A = 'A';
char B = 'B';
char C = 'C';
char D = 'D';
char E = 'E';
char F = 'F';
int totalCourseVal;
int totalCreditUnit;
int gpa;
Course1 = JOptionPane.showInputDialog("Enter your total score for Course1 ");
courseUnit1 = JOptionPane.showInputDialog("Enter credit unit of first course");
Course2 = JOptionPane.showInputDialog("Enter your total score for Course2 ");
courseUnit2 = JOptionPane.showInputDialog("Enter credit unit of second course");
Course3 = JOptionPane.showInputDialog("Enter your total score for Course3 ");
courseUnit3 = JOptionPane.showInputDialog("Enter credit unit of third course");
Course4 = JOptionPane.showInputDialog("Enter your total score for Course4 ");
courseUnit4 = JOptionPane.showInputDialog("Enter credit unit of fourth course");
Course5 = JOptionPane.showInputDialog("Enter your total score for Course5 ");
courseUnit5 = JOptionPane.showInputDialog("Enter credit unit of fifth course");
Course6 = JOptionPane.showInputDialog("Enter your total score for Course6 ");
courseUnit6 = JOptionPane.showInputDialog("Enter credit unit of sixth course");
Course7 = JOptionPane.showInputDialog("Enter your total score for Course7 ");
courseUnit7 = JOptionPane.showInputDialog("Enter credit unit of seventh course");
Course8 = JOptionPane.showInputDialog("Enter your total score for Course8 ");
courseUnit8 = JOptionPane.showInputDialog("Enter credit unit of eigth course");
Course9 = JOptionPane.showInputDialog("Enter your total score for Course9 ");
courseUnit9 = JOptionPane.showInputDialog("Enter credit unit of nineth course");
c1 = Integer.parseInt(Course1);
creditUnit1 = Integer.parseInt(courseUnit1);
c2 = Integer.parseInt(Course2);
creditUnit2 = Integer.parseInt(courseUnit2);
c3 = Integer.parseInt(Course3);
creditUnit3 = Integer.parseInt(courseUnit3);
c4 = Integer.parseInt(Course4);
creditUnit4 = Integer.parseInt(courseUnit4);
c5 = Integer.parseInt(Course5);
creditUnit5 = Integer.parseInt(courseUnit5);
c6 = Integer.parseInt(Course6);
creditUnit6 = Integer.parseInt(courseUnit6);
c7 = Integer.parseInt(Course7);
creditUnit7 = Integer.parseInt(courseUnit7);
c8 = Integer.parseInt(Course8);
creditUnit8 = Integer.parseInt(courseUnit8);
c9 = Integer.parseInt(Course9);
creditUnit9 = Integer.parseInt(courseUnit9);
if (c1 >= 70) {
cG1 = "A";
} else if (c1 >= 60) {
cG1 = "B";
} else if (c1 >= 50) {
cG1 = "C";
} else if (c1 >= 45) {
cG1 = "D";
} else if (c1 >= 40) {
cG1 = "E";
} else if (c1 < 40) {
cG1 = "F";
}
if (c2 >= 70) {
cG2 = "A";
} else if (c2 >= 60) {
cG2 = "B";
} else if (c2 >= 50) {
cG2 = "C";
} else if (c2 >= 45) {
cG2 = "D";
} else if (c2 >= 40) {
cG2 = "E";
} else if (c2 < 40) {
cG2 = "F";
}
if (c3 >= 70) {
cG3 = "A";
} else if (c3 >= 60) {
cG3 = "B";
} else if (c3 >= 50) {
cG3 = "C";
} else if (c3 >= 45) {
cG3 = "D";
} else if (c3 >= 40) {
cG3 = "E";
} else if (c3 < 40) {
cG3 = "F";
}
if (c4 >= 70) {
cG4 = "A";
} else if (c4 >= 60) {
cG4 = "B";
} else if (c4 >= 50) {
cG4 = "C";
} else if (c4 >= 45) {
cG4 = "D";
} else if (c4 >= 40) {
cG4 = "E";
} else if (c4 < 40) {
cG4 = "F";
}
if (c5 >= 70) {
cG5 = "A";
} else if (c5 >= 60) {
cG5 = "B";
} else if (c5 >= 50) {
cG5 = "C";
} else if (c5 >= 45) {
cG5 = "D";
} else if (c5 >= 40) {
cG5 = "E";
} else if (c5 < 40) {
cG5 = "F";
}
if (c6 >= 70) {
cG6 = "A";
} else if (c6 >= 60) {
cG6 = "B";
} else if (c6 >= 50) {
cG6 = "C";
} else if (c6 >= 45) {
cG6 = "D";
} else if (c6 >= 40) {
cG6 = "E";
} else if (c6 < 40) {
cG6 = "F";
}
if (c7 >= 70) {
cG7 = "A";
} else if (c7 >= 60) {
cG7 = "B";
} else if (c7 >= 50) {
cG7 = "C";
} else if (c7 >= 45) {
cG7 = "D";
} else if (c7 >= 40) {
cG7 = "E";
} else if (c7 < 40) {
cG7 = "F";
}
if (c8 >= 70) {
cG8 = "A";
} else if (c8 >= 60) {
cG8 = "B";
} else if (c8 >= 50) {
cG8 = "C";
} else if (c8 >= 45) {
cG8 = "D";
} else if (c8 >= 40) {
cG8 = "E";
} else if (c8 < 40) {
cG8 = "F";
}
if (c9 >= 70) {
cG9 = "A";
} else if (c9 >= 60) {
cG9 = "B";
} else if (c9 >= 50) {
cG9 = "C";
} else if (c9 >= 45) {
cG9 = "D";
} else if (c9 >= 40) {
cG9 = "E";
} else if (c9 < 40) {
cG9 = "F";
}
if (cG1 == "A") {
Course1Val = 5 * creditUnit1;
} else if (cG1 == "B") {
Course1Val = 4 * creditUnit1;
} else if (cG1 == "C") {
Course1Val = 3 * creditUnit1;
} else if (cG1 == "D") {
Course1Val = 2 * creditUnit1;
} else if (cG1 == "E") {
Course1Val = 1 * creditUnit1;
} else if (cG1 == "F") {
Course1Val = 0 * creditUnit1;
}
if (cG2 == "A") {
Course2Val = 5 * creditUnit2;
} else if (cG2 == "B") {
Course2Val = 4 * creditUnit2;
} else if (cG2 == "C") {
Course2Val = 3 * creditUnit2;
} else if (cG2 == "D") {
Course2Val = 2 * creditUnit2;
} else if (cG2 == "E") {
Course2Val = 1 * creditUnit2;
} else if (cG2 == "F") {
Course2Val = 0 * creditUnit2;
}
if (cG3 == "A") {
Course3Val = 5 * creditUnit3;
} else if (cG3 == "B") {
Course3Val = 4 * creditUnit3;
} else if (cG3 == "C") {
Course3Val = 3 * creditUnit3;
} else if (cG3 == "D") {
Course3Val = 2 * creditUnit3;
} else if (cG3 == "E") {
Course3Val = 1 * creditUnit3;
} else if (cG3 == "F") {
Course3Val = 0 * creditUnit3;
}
if (cG4 == "A") {
Course4Val = 5 * creditUnit4;
} else if (cG4 == "B") {
Course4Val = 4 * creditUnit4;
} else if (cG4 == "C") {
Course4Val = 3 * creditUnit4;
} else if (cG4 == "D") {
Course4Val = 2 * creditUnit4;
} else if (cG4 == "E") {
Course4Val = 1 * creditUnit4;
} else if (cG4 == "F") {
Course4Val = 0 * creditUnit4;
}
if (cG5 == "A") {
Course5Val = 5 * creditUnit5;
} else if (cG5 == "B") {
Course5Val = 4 * creditUnit5;
} else if (cG5 == "C") {
Course5Val = 3 * creditUnit5;
} else if (cG5 == "D") {
Course5Val = 2 * creditUnit5;
} else if (cG5 == "E") {
Course5Val = 1 * creditUnit5;
} else if (cG5 == "F") {
Course5Val = 0 * creditUnit5;
}
if (cG6 == "A") {
Course6Val = 5 * creditUnit6;
} else if (cG6 == "B") {
Course6Val = 4 * creditUnit6;
} else if (cG6 == "C") {
Course6Val = 3 * creditUnit6;
} else if (cG6 == "D") {
Course6Val = 2 * creditUnit6;
} else if (cG6 == "E") {
Course6Val = 1 * creditUnit6;
} else if (cG6 == "F") {
Course6Val = 0 * creditUnit6;
}
if (cG7 == "A") {
Course7Val = 5 * creditUnit7;
} else if (cG7 == "B") {
Course7Val = 4 * creditUnit7;
} else if (cG7 == "C") {
Course7Val = 3 * creditUnit7;
} else if (cG7 == "D") {
Course7Val = 2 * creditUnit7;
} else if (cG7 == "E") {
Course7Val = 1 * creditUnit7;
} else if (cG7 == "F") {
Course7Val = 0 * creditUnit7;
}
if (cG8 == "A") {
Course8Val = 5 * creditUnit8;
} else if (cG8 == "B") {
Course8Val = 4 * creditUnit8;
} else if (cG8 == "C") {
Course8Val = 3 * creditUnit8;
} else if (cG8 == "D") {
Course8Val = 2 * creditUnit8;
} else if (cG8 == "E") {
Course8Val = 8 * creditUnit8;
} else if (cG8 == "F") {
Course8Val = 0 * creditUnit8;
}
if (cG9 == "A") {
Course9Val = 5 * creditUnit9;
} else if (cG9 == "B") {
Course9Val = 4 * creditUnit9;
} else if (cG9 == "C") {
Course9Val = 3 * creditUnit9;
} else if (cG9 == "D") {
Course9Val = 2 * creditUnit9;
} else if (cG9 == "E") {
Course9Val = 9 * creditUnit9;
} else if (cG9 == "F") {
Course9Val = 0 * creditUnit9;
}
totalCourseVal = (Course1Val + Course2Val + Course3Val + Course4Val + Course5Val + Course6Val + Course7Val + Course8Val + Course9Val);
totalCreditUnit = (creditUnit1 + creditUnit2 + creditUnit3 + creditUnit4 + creditUnit5 + creditUnit6 + creditUnit7 + creditUnit8 + creditUnit9);
gpa = totalCourseVal / totalCreditUnit;
JOptionPane.showMessageDialog(null, "Your Grade Point Average is" + gpa, "GRADE POINT AVERAGE CALCULATOR", JOptionPane.PLAIN_MESSAGE);
System.exit(0);
}
答案 0 :(得分：0)
不要将某些变量保留为未初始化，而是将它们初始化为：
int Course1Val = 0, Course2Val = 0, Course3Val = 0, Course4Val = 0, Course5Val = 0, Course6Val = 0, Course7Val = 0, Course8Val = 0, Course9Val = 0;
String cG1 = "", cG2 = "", cG3 = "", cG4 = "", cG5 = "", cG6 = "", cG7 = "", cG8 = "", cG9 = "";
答案 1 :(得分：0)
首先，熟悉在问题/答案/评论中发布源代码。
例如：How do I format my code blocks?
回到你的问题，你试图用字符串值（“A”）比较和局部变量（尚未初始化的cG1）。确保在使用之前初始化所有变量（分配一些值）。