1. CHAPTER 4 Selection Making Decision
Logical Data and Operator
Two Way Selection
Multi way Selection
More Standard Library Function
A Menu Program
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

2. 4.1 Logical Data and Operator
how logical data is represented in C
Operator Meaning Precedence
=============================
! Not 15
&& Logical AND 5
|| Logical OR 4
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

3. Logical operator truth table
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

4. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

5. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

6. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Original Expression Simplified
============================
!(x < y) x >= y
!(x > y) x <= y
!(x != y) x == y
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

7. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
4.2 Two Way Selection
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

8. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

9. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Null else statement
Null if statement
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

10. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Nested If statement
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

11. Example of nested if statement
if ( a <= b) {
if( a < b)
printf(“%d < %d”, a, b);
else
printf(“%d == %d”, a, b); }
printf(“%d > %d”, a, b);
if ( a <= b)
if( a < b)
printf(“%d < %d”, a, b);
else
printf(“%d == %d”, a, b);
printf(“%d > %d”, a, b);
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

12. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Dangling else problem
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

13. Dangling else solution
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

14. Conditional Expression
expression ? expression1 : expression2;
a == b ? c-- : c++;
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

15. Example- calculate tax
bracket taxable tax rate
=====================
1 <= %
– %
– %
– %
5 > = %
Income 23000
in bracket Rate Tax
2% 200
% 500
7% 210
Total 910
Income 18000
in bracket Rate Tax
2% 200
% 400
Total 600
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

16. Example- calculate tax
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

17. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Program Calculate Taxes
Calculate taxes based on marginal tax brackets.
1 Get income data (total income, taxes paid, dependencies)
2 Calculate taxes (total tax, tax due)
3 Print information
End Calculate Taxes
==================== calcTaxes ==================
calcTaxes
1 taxable income = total income – dependent exemptions
2 total tax = tax for bracket 1
+ tax for bracket 2
+ tax for bracket 3
+ tax for bracket 4
+ tax for bracket 5
tax due = total tax – taxes paid
End calcTaxes
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

18. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
#include <stdio.h>
#define LOWEST 0.0
#define HIGHEST
#define LIMIT
#define LIMIT
#define LIMIT
#define LIMIT
#define RATE1 02
#define RATE2 05
#define RATE3 07
#define RATE4 10
#define RATE1 15
#define DEDN_PER_DPNDNT 1000
/*Prototype*/
void getData(double *totalIncome,
double *taxpaid,
int *numofDpndnts);
void calcTaxes(double totalIncome,
double taxPaid,
int numOfDpndnts,
double *taxableIncome, *totalTax,
double *taxDue);
void printInformation(double totalIncome,
double taxpaid,
int numofDpndnts,
double totalTax,paidTax, taxDue);
double bracketTax(double income,
double startLimit,
double stopLimit,
int rate);
int main() {
int numOfDpndnts;
double taxDue,taxPaid,totalIncome,
taxableIncome, totalTax;
getData(&totalIncome,&taxPaid, &numOfDpndnts);
calcTaxes(totalIncome,taxPaid, numOfDpndnts, &taxableIncome, &totalTax, &taxDue);
printInformation(totalIncome,taxableIncome,numOfDpndnts,totakTax, taxPaid,taxDue);
return 0; }
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

19. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
void getData(double *totalIncome,
double *taxpaid,
int *numofDpndnts) {
printf(“Enter total income for last year:”);
scanf(“%lf”,totalIncome);
printf(“Enter total payrol deduction:”);
scanf(“%lf”,taxPaid);
printf(“Enter no of dependants:”);
scanf(“%lf”,numDpndnts);
return; }
===========================
void calcTaxes(double totInc,
double taxPaid,
int numOfDpndnts,
double *taxableIncome, *totalTax,
double *taxDue)
*taxableInc = totInc – ( numOfDpndnts * DEDN_PER_DPNDNT);
*totTax = bracketTax(*taxableIncome,
LOWEST, LIMIT1, RATE1)
+ bracketTax(*taxableIncome,
LIMIT1, LIMIT2, RATE2)
LIMIT2, LIMIT3, RATE3)
LIMIT3, LIMIT4, RATE4)
LIMIT4, HIGHEST, RATE5);
*taxDue = * totTax – taxPaid;
return; }
double bracketTax(double income,double startLimit,double stopLimit,int rate); {
double tax;
if(income <= startLimit)
tax = 0.0;
else
if(income > startLimit && income <=stopLimit)
tax = (income – startLimit) * rate /100.0;
tax = (stopLimit – startLimit) * rate / 100.0;
return tax;
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

20. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Figure 5-19
4.3 Multi Way Selection
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

21. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Figure 5-20
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

22. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Figure 5-21
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

23. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Figure 5-22
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

24. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Figure 5-23
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

25. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Figure 5-24
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

26. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Example: get grade
if ( mark >= 90)
grade = ‘A’;
else if(mark >= 80)
grade = ‘B’;
else if(mark >= 70)
grade = ‘C’;
else if(mark >= 60)
grade = ‘D’;
else
grade = ‘F’;
printf(“Your grade is: %c”, grade);
if ( cgpa >= 3.0)
printf(“Very Good”);
else if(cgpa >= 2.0)
printf(“OK”);
else if (cgpa >=1.7)
printf(“You want to leave?”);
else
printf(“Bye”);
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

27. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Figure 5-27
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

28. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Figure 5-28
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

29. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Figure 5-29 T F
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

30. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Example:
char letter;
printf(“enter letter:”);
scanf(“%c”,&letter);
if((letter== ‘a’ )|| (letter== ‘e’)||( letter == ‘i’))
printf(“”vokal);
else
printf(“konsonen”);
printf(“enter letter:”);
scanf(“%c”,&letter);
switch(value) {
case ‘a’:
case ‘e’:
case ‘i’:
printf(“vokall”);
break;
default:
printf(“konsonan”); }
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

31. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Example:
printf(“enter letter:”);
scanf(“%c”,&letter);
switch(value) {
case ‘a’:
case ‘e’:
case ‘i’:
case ‘A’:
case ‘E’:
case ‘I’:
printf(“vokall”);
break;
default:
printf(“konsonan”); }
printf(“enter letter:”);
scanf(“%c”,&letter);
letter = toupper(letter);
switch(value) {
case ‘A’:
case ‘E’:
case ‘I’:
printf(“vokall”);
break;
default:
printf(“konsonan”); }
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

32. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Example:
choice = getSelection();
switch(choice) {
case ‘1’:
checkBalance();
break;
case ‘2’:
cashWithdrawal();
default:
printf(“Good Bye”); }
int getSelection(void) {
int select;
printf(“\n1. Check Balance.”);
printf(“\n2. Withdraw Cash.”);
printf(“\n3. Quit“);
printf(“\nenter selection:”);
scanf(“%c”,& select);
return select; }
void checkBalance(void) ..
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

33. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
Figure 5-26
int getOption(void);
void getData(float *num1, float *num2);
float calc(int option ,float num1, float num2);
float add(float num1,float num2);
float sub(float num1,float num2);
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

34. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
A MENU PROGRAM pg 207
int getOption(void) {
int option;
printf(“\n1.ADD”);
printf(“\n2.SUBTRACT”);
printf(“\n3.MULTIPLY”);
printf(“\n4.DIVIDE”);
printf(“\nEnter your selection:”);
scanf(“%d”,&option);
return option; }
intmain(void) {
int option;
float num1,num2,result;
option = getOption();
getData(&num1,&num2);
result=calc(option,num1,num2);
printResult(num1,num2,result,option);
return 0; }
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

35. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
float calc(int option, float num1, float num2) {
float result;
switch(option)
case 1:result = add(num1,num2);
break;
case 2:result = sub(num1,num2);
case 3:result = mul(num1,num2);
case 4:
if(num2 == 0.0)
printf(“Error divide by 0);
exit(1); }
else
result = dvd(num1,num2);
float add(float num1, float num2) {
float res;
res = num1 + num2;
return res; }
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision

36. DDC 1123 Programming 1(C) Chap 4 Selection Making Decision
KUIZ 2 Pilihan
Tuliskan sebuah aturcara yang dapat menerima
input satu digit(0 hingga 9) dan kemudiannya
mencetak nilainya dalam perkataan.
contoh:
Jika input 5
Maka output lima
DDC 1123 Programming 1(C) Chap 4 Selection Making Decision