Chapter 3 exercises and exercises in C language programming

[Exercise 3-1]
No; because all possible conditions are covered.
[Exercise 3-2]
# Include <stdio. h>
Int main (void)
{
Int y;
Double X;
Printf ("Enter X :");
Scanf ("% lf", & X );
If (x <0)
Y =-1;
Else if (x = 0)
Y = 0;
Else
Y = 1;
Printf ("Y = Sign (% F) = % d \ n", x, y );
Return 0;
}
[Exercise 3-3]
# Include <stdio. h>
Int main (void)
{
Char ch;
Int I, digit, letter, Se, other;
Printf ("Enter 15 characters :");
Digit = letter = Se = Other = 0;
For (I = 1; I <= 15; I)
{
Ch = getchar ();
If (CH> = '0' & Ch <= '9 ')
Digit;
Else if (CH> = 'A' & Ch <= 'Z') | (CH> = 'A' & Ch <= 'Z '))
Letter;
Else if (CH = ''| CH = '\ n ')
Se;
Else
Other;
}
Printf ("digit = % d, letter = % d, Se = % d, other = % d \ n", digit, letter, Se, other );
Return 0;
}
[Exercise 3-4]
The output value is "Price = 0.0". If the break is not used, not only the statement segment is met, but also all subsequent statement segments are executed.
[Exercise 3-5]
# Include <stdio. h>
Int main (void)
{
Double value1, value2;
Char operato;
Printf ("type in an expression :");
Scanf ("% lf % C % lf", & value1, & operato, & value2 );
Switch (operato)
{
Case '':
Printf ("= %. 2f \ n", value1 value2 );
Break;
Case '-':
Printf ("= %. 2f \ n", value1-value2 );
Break;
Case '*':
Printf ("= %. 2f \ n", value1 * value2 );
Break;
Case '/':
If (value2 = 0)
Printf ("You are wrong \ n ");
Else
Printf ("= %. 2f \ n", value1/value2 );
Break;
Default:
Printf ("unknown operator \ n ");
Break;
}
Return 0;
}
[Exercise 3-6]
# Include <stdio. h>
Int main (void)
{
Char level;
Printf ("Enter level (~ E ):");
Level = getchar ();
Switch (level)
{
Case 'A ':
Printf ("90 ~ 100 \ n ");
Break;
Case 'B ':
Printf ("80 ~ 89 \ n ");
Break;
Case 'C ':
Printf ("70 ~ 79 \ n ");
Break;
Case 'D ':
Printf ("60 ~ 69 \ n ");
Break;
Case 'E ':
Printf ("0 ~ 59 \ n ");
Break;
Default:
Printf ("Wrong level \ n ");
Break;
}
Return 0;
}
[Exercise 3-7]
# Include <stdio. h>
Int main (void)
{
Int I, choice;
Double price;
Printf ("[1] apples \ n ");
Printf ("[2] pears \ n ");
Printf ("[3] oranges \ n ");
Printf ("[4] Grapes \ n ");
Printf ("[0] exit \ n ");
For (I = 1; I <= 5; I)
{
Printf ("Enter choice :");
Scanf ("% d", & choice );
If (choice = 0)
{
Printf ("Byebye! \ N ");
Break;
}
Switch (choice)
{
Case 1:
Price = 3.00;
Break;
Case 2:
Price = 2.50;
Break;
Case 3:
Price = 4.10;
Break;
Case 4:
Price = 10.20;
Break;
Default:
Price = 0.00;
}
Printf ("Price = %. 2f \ n", price );
If (I = 5) & (choice! = 0 ))
Printf ("You have used five times. Please try again. \ n ");
}
Return 0;
}
[Exercise 3-8]
# Include <stdio. h>
Int main (void)
{
Int year;
Printf ("Enter year :");
Scanf ("% d", & year );
If (Year % 4 = 0 & year0! = 0) | (Year @ 0 = 0 ))
{
Printf ("It is leap year. \ n ");
}
Else
{
Printf ("It isn' t leap year. \ n ");
}
Return 0;
}
[Exercise 3-9]
# Include <stdio. h>
Int main (void)
{
Int N, I, count;
Double total, grade;
Printf ("Enter N :");
Scanf ("% d", & N );
Total = 0;
Count = 0;
For (I = 1; I <= N; I)
{
Printf ("enter grade # % d:", I );
Scanf ("% lf", & grade );
Total = total grade;
If (grade> = 60)
{
Count;
}
}
Printf ("The avaerage = %. 2f \ n", total/N );
Printf ("the number of qualifies = % d \ n", count );
Return 0;
}
[Exercise 3-10]
# Include <stdio. h>
Int main (void)
{
Double X, Y;
Printf ("Enter X :");
Scanf ("% lf", & X );
If (x <0)
{
Y = 0;
}
If (x> = 0)
{
If (x <= 15)
{
Y = 4 * X/3;
}
Else
{
Y = 2.5 * x-10.5;
}
}
Printf ("F (%. 2f) = %. 2f \ n", x, y );
Return 0;
}
[Exercise 3-11]
The conditions for rewriting the first two statements are: X less than 1; X greater than or equal to 1 and less than 2. The execution conditions of the two statements after rewriting are: X less than 1; X greater than or equal to 2.
[Exercise 3-1]
# Include <stdio. h>
# Include <math. h>
Int main (void)
{
Int A, B, C;
Double area, S, perimeter, part;
Printf ("enter :");
Scanf ("% d", & );
Printf ("Enter B :");
Scanf ("% d", & B );
Printf ("Enter C :");
Scanf ("% d", & C );
If (a B> C) & (B c> A) & (c a> B ))
{
S = (a B C)/2;
Part = S * (S-A) * (S-B) * (s-c );
Area = SQRT (part );
Perimeter = a B C;
Printf ("Area = %. 2f \ n", area );
Printf ("Perimeter = %. 2f \ n", perimeter );
}
Else
{
Printf ("these sides do not correspond to a valid triangle. \ n ");
}
Return 0;
}
[Exercise 3-2]
# Include <stdio. h>
Int main (void)
{
Int salary, rate;
Double tax;
Printf ("Enter salary :");
Scanf ("% d", & Salary );
If (salary <= 850)
{
Rate = 0;
}
Else if (salary <= 1350)
{
Rate = 5;
}
Else if (salary <= 2850)
{
Rate = 10;
}
Else if (salary <= 5850)
{
Rate = 15;
}
Else
{
Rate = 20;
}
Tax = Rate * (salary-850)/100;
Printf ("tax = %. 2f \ n", tax );
Return 0;
}
[Exercise 3-3]
# Include <stdio. h>
Int main (void)
{
Int km, min;
Double part, money;
Printf ("Enter km :");
Scanf ("% d", & km );
Printf ("Enter min :");
Scanf ("% d", & min );
If (km <= 3)
{
Money = 10;
}
Else
{
Money = 10 (km-3) * 3;
}
If (min> 0)
{
Part = min/5;
Money = money part * 3;
}
Printf ("Money = %. 0f \ n", money );
Return 0;
}
[Exercise 3-4]
# Include <stdio. h>
Int main (void)
{
Int A, B, C, D, E, N, I;
Double grade, sum, average;
Printf ("Enter N :");
Scanf ("% d", & N );
A = B = c = d = E = sum = 0;
For (I = 1; I <= N; I)
{
Printf ("enter grade # % d:", I );
Scanf ("% lf", & grade );
Sum = sum grade;
If (Grade <60)
{
E;
}
Else if (Grade <70)
{
D;
}
Else if (Grade <80)
{
C;
}
Else if (Grade <90)
{
B;
}
Else
{
A;
}
}
Average = sum/N;
Printf ("average = %. 2f \ n", average );
Printf ("A = % d \ NB = % d \ NC = % d \ nD = % d \ Ne = % d \ n", a, B, c, d, e );
Return 0;
}
[Exercise 3-5]
# Include <stdio. h>
Int main (void)
{
Int I;
For (I = 2000; I <= 3000; I)
{
If (I % 4 = 0) & (I0! = 0) | (I @ 0 = 0 ))
{
Printf ("% d \ n", I );
}
}
Return 0;
}