C Language Growth Learning problem (v)

17, to find the real roots of the equation ax2+bx+c=0 (requires a, B, C values from the keyboard input, a!=0).

1#include <stdio.h>2#include <math.h>3 4 voidMainvoid)5 {6     intA, B, C;7     floatDelta, X1, x2;8     9printf"Input A, B, c:\n");Tenscanf"%d%d%d", &a, &b, &c); OneDelta = b * B-4AC; A     if(Delta <0) -printf"No Real root.\n"); -     Else the     { -X1 = (-B + sqrt (delta))/(2*a); -x2 = (-b-sqrt (delta))/(2*a); -printf"x1 =%f, x2 =%f\n", x1, x2); +     } -}

Results:

1.Input A, B, C:

4 8 1

x1 = 2.118034, x2 = 0.118034

2.Input A, B, C:

2 4 3

No Real Root.

3.Input A, B, C:

4 12 9

x1 = 1.500000, x2 = 1.500000

Mark:

If your program uses math library functions, you must add command line # include <math.h> at the beginning of the program

18, write the program to achieve the following functions: Enter a year of the years, to determine whether it is a leap.

1#include <stdio.h>2 3 voidMainvoid)4 {5     intYear , flag;6 7scanf"%d", &Year );8     if(Year% -==0)9Flag =1;Ten     Else One     { A         if(Year%4!=0) -Flag =0; -         Else the         { -             if(Year% -!=0) -Flag =1; -             Else +Flag =0 -         } +     } A     if(Flag = =1) atprintf"%d is a leap year.\n", year); -     Else -printf"%d is not a leap year.\n", year); -}

19. Write a program that evaluates the values of the following piecewise functions, where the value of x is entered from the keyboard.

1#include <stdio.h>2 {3     floatx, y;4 5printf"Input data:\n");6scanf"%f", &x);7     if(X <0)8y =0;9     Else if(X <Ten)Teny = x * x * x +5; One     Else if(X < -) Ay =2* x * x-x-6; -     Else if(X < -) -y = x * x +1; the     Else -y = x +3; -printf"x =%f, y =%f\n", x, y); -}

20, analyze the following procedure, observe its output.

1#include <stdio.h>2 3 voidMainvoid)4 {5     intA;6 7scanf"%", &a);8     Switch(a)9     {Ten          Case 1: printf ("A"); One          Case 2: printf ("B"); A          Case 3: printf ("C"); Break; -         default: printf ("D"); -     } the}

Results:

(1) 1

Abc

(2) 2

Bc

(3) 3

C

(4) 4

D

C Language Growth Learning problem (v)