printwriter - I keep only getting these compiling answers in 3 methods. JAVA -
please ignore sloppy coding. i'm pretty new java , trying project school. can't find causing error
decrossdiscipline.java:455: error: unreported exception filenotfoundexception; must caught or declared thrown printwriter outputfile = new printwriter(filename); ^ decrossdiscipline.java:533: error: unreported exception filenotfoundexception; must caught or declared thrown printwriter outputfile = new printwriter(filename); ^ decrossdiscipline.java:623: error: unreported exception filenotfoundexception; must caught or declared thrown printwriter outputfile = new printwriter(filename); ^ 3 errors this program getting errors in. please help. feel need pair of eyes spot problem me. import java.util.scanner; import java.io.*;
public class decrossdiscipline { public static void main(string[] args) throws ioexception { scanner keyboard = new scanner(system.in); int deselection; int method; int method2; int method3; blanklines(); system.out.println("\tdifferential equation cross discipline project"); system.out.println(); demenu(); deselection = keyboard.nextint(); if (deselection<1) { system.out.println(); system.out.println("that not choice. please try again.\n"); demenu(); deselection = keyboard.nextint(); } if (deselection>3) { system.out.println(); system.out.println("that not choice. please try again.\n"); demenu(); deselection = keyboard.nextint(); } if (deselection==1) {menu1(); method=keyboard.nextint(); if (method<1) { system.out.println(); system.out.println("not valid choice!"); menu1(); method=keyboard.nextint(); } if (method>2) { system.out.println(); system.out.println("not valid choice!"); menu1(); method=keyboard.nextint(); } if (method==1) {rungekutta1(); } if (method==2) {euler1(); } } if (deselection==2) {menu2(); method2=keyboard.nextint(); if (method2<1) { system.out.println(); system.out.println("not valid choice!"); menu2(); method2=keyboard.nextint(); } if (method2>2) { system.out.println(); system.out.println("not valid choice!"); menu2(); method2=keyboard.nextint(); } if (method2==1) {rungekutta2(); } if (method2==2) {euler2(); } } if (deselection==3) {menu3(); method3=keyboard.nextint(); if (method3<1) { system.out.println(); system.out.println("not valid choice!"); menu3(); method3=keyboard.nextint(); } if (method3>2) { system.out.println(); system.out.println("not valid choice!"); menu3(); method3=keyboard.nextint(); } if (method3==1) {rungekutta3(); } if (method3==2) {euler3(); } } } public static void blanklines() { (int l=0; l<11; l++) { system.out.println(); } } public static void demenu() { system.out.println("1. y'=(x+1)^2\n" + "2. y'=3(x^2)*(y-4)^2\n" + "3. y'=3(x^2)*(y-2)^2"); system.out.print("please enter number of \ndifferential equation want use: "); } public static void menu1() { system.out.print("\n1. runge kutta\n" + "2. euler\n"); system.out.print("please enter number of \nmethod want use: "); } public static void menu2() { system.out.print("\n1. runge kutta\n" + "2. euler\n"); system.out.print("please enter number of \nmethod want use: "); } public static void menu3() { system.out.print("\n1. runge kutta\n" + "2. euler\n"); system.out.print("please enter number of \nmethod want use: "); } public static void rungekutta1() throws ioexception { scanner keyboard = new scanner(system.in); double y; double h; double x; double i; system.out.print("\nplease enter initial y value: "); y = keyboard.nextdouble(); system.out.print("please enter initial x value: "); x = keyboard.nextdouble(); system.out.print("please enter h value: "); h = keyboard.nextdouble(); if (h<=0) { system.out.println("\nenter valid h value"); system.out.print("please enter h value: "); h = keyboard.nextdouble(); } system.out.print("please enter amount of results want: "); = keyboard.nextint(); if (i<1) { system.out.println("\nplease enter amount of 1 or greater"); system.out.print("please enter amount of results want: "); = keyboard.nextint(); } system.out.println(); system.out.print("your results printed\n" + "to file. please enter name\n" + "for file: "); string filename = keyboard.next(); system.out.println(); system.out.println("x values\t" + "y values"); system.out.println("___________________________"); double k1, k2, k3, k4, k5, k6, k7, k8, k9, k10; file file = new file(filename); printwriter outputfile = new printwriter(filename); (int number=1; number<=i; number++) { system.out.printf("when x = %.2f\t", x); system.out.printf("y = %.4f\n", y); outputfile.printf("when x = %.2f\t" + "y = %.4f", x,y); outputfile.println(); k1 = math.pow(x+1, 2); k2 = x+h/2; k3 = y+(h/2)*k1; k4 = math.pow(k2+1, 2); k5 = y+(h/2)*k2; k6 = math.pow(k2+1, 2); k7 = x+h; k8 = y+h*k6; k9 = math.pow(k7+1, 2); k10 = y+h/6*(k1+2*(k4+k6)+k9); x = x+h; y = k10; } outputfile.close(); } public static void euler1()throws ioexception { scanner keyboard = new scanner(system.in); double y; double h; double x; double i; system.out.print("\nplease enter initial y value: "); y = keyboard.nextdouble(); system.out.print("please enter initial x value: "); x = keyboard.nextdouble(); system.out.print("please enter h value: "); h = keyboard.nextdouble(); if (h<=0) { system.out.println("\nenter valid h value"); system.out.print("please enter h value: "); h = keyboard.nextdouble(); } system.out.print("please enter amount of results want: "); = keyboard.nextint(); if (i<1) { system.out.println("\nplease enter amount of 1 or greater"); system.out.print("please enter amount of results want: "); = keyboard.nextint(); } system.out.println(); system.out.print("your results printed\n" + "to file. please enter name\n" + "for file: "); string filename = keyboard.next(); system.out.println(); system.out.println("x values\t" + "y values"); system.out.println("___________________________"); double e1, e2, e3, e4, e5; file file = new file(filename); printwriter outputfile = new printwriter(filename); (int number=1; number<=i; number++) { system.out.printf("while x = %.2f\t", x); system.out.printf("y = %.4f\n", y); outputfile.printf("when x = %.2f\t" + "y = %.4f", x,y); outputfile.println(); e1 = math.pow(x+1, 2); e2 = x+h; e3 = y+(h*e1); e4 = math.pow(e2+1, 2); e5 = y+h/2*(e1+e4); x = x+h; y = e5; } outputfile.close(); } public static void rungekutta2() throws ioexception { scanner keyboard = new scanner(system.in); double y; double h; double x; int i; system.out.print("\nplease enter initial y value: "); y = keyboard.nextdouble(); system.out.print("please enter initial x value: "); x = keyboard.nextdouble(); system.out.print("please enter h value: "); h = keyboard.nextdouble(); if (h<=0) { system.out.println("\nenter valid h value"); system.out.print("please enter h value: "); h = keyboard.nextdouble(); } system.out.print("please enter amount of results want: "); = keyboard.nextint(); if (i<1) { system.out.println("\nplease enter amount of 1 or greater"); system.out.print("please enter amount of results want: "); = keyboard.nextint(); } system.out.println(); system.out.print("your results printed\n" + "to file. please enter name\n" + "for file: "); string filename = keyboard.next(); system.out.println(); system.out.println("x values\t" + "y values"); system.out.println("___________________________"); double r1, r2, r3, r4, r5, r6, r7, r8, r9, r10; file file = new file(filename); printwriter outputfile = new printwriter(filename); (int number=1; number<=i; number++) { system.out.printf("while x = %.2f\t", x); system.out.printf("y = %.4f\n", y); outputfile.printf("when x = %.2f\t" + "y = %.4f", x,y); outputfile.println(); r1 = 3*(x*x)*math.pow((y-4), 2); r2 = x+h/2; r3 = y+(h/2)*r1; r4 = (3*(r2*r2))*math.pow(r3-4, 2); r5 = y+(h/2)*r4; r6 = (3*(r2*r2))*math.pow(r5-4, 2); r7 = x+h; r8 = y+h*r6; r9 = (3*(r7*r7))*math.pow(r8-4, 2); r10 = y+h/6*(r1+2*(r4+r6)+r9); x = x+h; y = r10; } outputfile.close(); } public static void euler2() { int i; double y; double h; double x; scanner keyboard = new scanner(system.in); system.out.print("\nplease enter initial y value: "); y = keyboard.nextdouble(); system.out.print("please enter initial x value: "); x = keyboard.nextdouble(); system.out.print("please enter h value: "); h = keyboard.nextdouble(); if (h<=0) { system.out.println("\nenter valid h value"); system.out.print("please enter h value: "); h = keyboard.nextdouble(); } system.out.print("please enter amount of results want: "); = keyboard.nextint(); if (i<1) { system.out.println("\nplease enter amount of 1 or greater"); system.out.print("please enter amount of results want: "); = keyboard.nextint(); } system.out.println(); system.out.print("your results printed\n" + "to file. please enter name\n" + "for file: "); string filename = keyboard.next(); system.out.println(); system.out.println("x values\t" + "y values"); system.out.println("___________________________"); double e1, e2, e3, e4, e5; file file = new file(filename); printwriter outputfile = new printwriter(filename); (int number=0; number<=i; number++) { system.out.printf("while x = %.2f\t", x); system.out.printf("y = %.4f\n", y); outputfile.printf("when x = %.2f\t" + "y = %.4f", x,y); outputfile.println(); e1 = 3*(x*x)*math.pow((y-4), 2); e2 = x+h; e3 = y+h*e1; e4 = (3*(e2*e2))*math.pow((e3-4), 2); e5 = y+h/2*(e1+e4); x = x+h; y = e5; } outputfile.close(); } public static void rungekutta3() { scanner keyboard = new scanner(system.in); double y; double h; double x; int i; system.out.print("\nplease enter initial y value: "); y = keyboard.nextdouble(); system.out.print("please enter initial x value: "); x = keyboard.nextdouble(); system.out.print("please enter h value: "); h = keyboard.nextdouble(); if (h<=0) { system.out.println("\nenter valid h value"); system.out.print("please enter h value: "); h = keyboard.nextdouble(); } system.out.print("please enter amount of results want: "); = keyboard.nextint(); if (i<1) { system.out.println("\nplease enter amount of 1 or greater"); system.out.print("please enter amount of results want: "); = keyboard.nextint(); } system.out.println(); system.out.print("your results printed\n" + "to file. please enter name\n" + "for file: "); string filename = keyboard.next(); system.out.println(); system.out.println("x values\t" + "y values"); system.out.println("___________________________"); double r1, r2, r3, r4, r5, r6, r7, r8, r9, r10; file file = new file(filename); printwriter outputfile = new printwriter(filename); (int number=1; number<=i; number++) { system.out.printf("while x = %.2f\t", x); system.out.printf("y = %.4f\n", y); outputfile.printf("when x = %.2f\t" + "y = %.4f", x,y); outputfile.println(); r1 = 3*(x*x)*math.pow((y-2), 2); r2 = x+h/2; r3 = y+(h/2)*r1; r4 = (3*(r2*r2))*math.pow(r3-2, 2); r5 = y+(h/2)*r4; r6 = (3*(r2*r2))*math.pow(r5-2, 2); r7 = x+h; r8 = y+h*r6; r9 = (3*(r7*r7))*math.pow(r8-2, 2); r10 = y+h/6*(r1+2*(r4+r6)+r9); x = x+h; y = r10; } outputfile.close(); } public static void euler3() { int i; double y; double h; double x; scanner keyboard = new scanner(system.in); system.out.print("\nplease enter initial y value: "); y = keyboard.nextdouble(); system.out.print("please enter initial x value: "); x = keyboard.nextdouble(); system.out.print("please enter h value: "); h = keyboard.nextdouble(); if (h<=0) { system.out.println("\nenter valid h value"); system.out.print("please enter h value: "); h = keyboard.nextdouble(); } system.out.print("please enter amount of results want: "); = keyboard.nextint(); if (i<1) { system.out.println("\nplease enter amount of 1 or greater"); system.out.print("please enter amount of results want: "); = keyboard.nextint(); } system.out.println(); system.out.print("your results printed\n" + "to file. please enter name\n" + "for file: "); string filename = keyboard.next(); system.out.println(); system.out.println("x values\t" + "y values"); system.out.println("___________________________"); double e1, e2, e3, e4, e5; file file = new file(filename); printwriter outputfile = new printwriter(filename); (int number=0; number<=i; number++) { system.out.printf("while x = %.2f\t", x); system.out.printf("y = %.4f\n", y); outputfile.printf("when x = %.2f\t" + "y = %.4f", x,y); outputfile.println(); e1 = 3*(x*x)*math.pow((y-2), 2); e2 = x+h; e3 = y+h*e1; e4 = (3*(e2*e2))*math.pow((e3-2), 2); e5 = y+h/2*(e1+e4); x = x+h; y = e5; } outputfile.close(); } }
on method
public static void euler1()throws ioexception you declare method might throw ioexception filenotfoundexception.
you have in every method might happen including.
public static void euler2() { i suggest use ide to
- help format code.
- refactor class there not many unrelated methods in it.
- add these exceptions you type.
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