The document discusses various decision making and flow control statements in C++ including if, if-else, nested if-else, switch, logical operators, the conditional operator, continue, and goto. It provides syntax examples and flow charts to illustrate the usage and flow of each statement type. Key points covered include single and multi-statement syntax, matching else clauses, break in switch, operator precedence, and using continue to skip the rest of the current loop iteration.

1. DECISIONS
LECTURE # 4

2. if Statement
Syntax
• Single statement if
if(condition)
statement;
• Multi statement if
if(condition)
{
statement1;
statement2;
}

3. if Statement Flow Chart
Body of if
Test
Expression
Exit
FalseTrue

4. if Statement Example
#include<iostream>
using namespace std;
int main()
{
int num;
cout<<“Enter a number”;
cin>>num;
if(num>100)
{
cout<<“Number is greater than 100”;
cout<<endl;
}
return 0;
}

5. Example
• Generate even number using if and for
loop.
#include<iostream>
#include<conio.h>
using namespace std;
int main()
{
int i;
for(i=0;i<=100;i++)
{
if(i%2==0)
cout<<i<<endl;
}
getche();
return 0;
}

6. If…else Statement
Syntax
• Single statement if...else
if(condition)
statement;
else
statement;
• Multi statement if…else
if(condition)
{
statement1;
statement2;
}
else
{
statement1;
statement2;
}

7. If…else Statement Flow Chart
Body of if
Test
Expression
Exit
FalseTrue
Body of else

8. If…else Statement Example
#include<iostream>
using namespace std;
int main()
{
int num;
cout<<“Enter a number”;
cin>>num;
if(num>100)
{
cout<<“Number is greater than 100”;
cout<<endl;
}
else
cout<<“Number is not greater than 100”;
return 0;
}

9. If…else Statement Example
#include<iostream>
#include<conio.h>
using namespace std;
int main()
{
int chcount=-1;
int wdcount=1;
char ch=‘a’;
cout<<“Enter a phrasen”;
while(ch!=‘r’)
{
ch=getche();
if(ch==‘ ‘)
wdcount++;
else
chcount++;
}
cout<<“nWord
count=“<<wdcount<<endl;
cout<<“Character
count=“<<chcount;
return 0;
}

10. Nested If…else Statement
Syntax
• Single statement if...else
if(condition)
statement;
else
statement;
• Multi statement if…else
if(condition)
{
statement1;
statement2;
}
else
{
statement1;
statement2;
}
(condition)
(condition)

11. Nested If…else Example
#include<iostream>
#include<conio.h>
using namespace std;
int main()
{
char dir=‘a’;
int x=0,y=0;
while(dir!=‘r’)
{
cout<<“Enter your location”;
dir=getche();
if(dir==‘n’)
y--;
else if(dir==‘s’)
y++;
else if(dir==‘e’)
x++;
else if(dir==‘w’)
x--;
}
return 0;
}

12. Matching else
#include<iostream>
#include<conio.h>
int main()
{
int a,b,c;
cout<<“Enter three numbers:”;
cin>>a>>b>>c;
if(a==b)
if(b==c)
cout<<“b and c are same”;
else
cout<<“b and c are different”;
getche();
retutn 0;
}

13. Switch Statement
Syntax
switch(n)
{
case 1:
statement
statement;
break;
case 2:
statement
statement;
break;
default:
statement;
statement;
}
1st case body
2nd case body
Default body
Break causes exit from switch

14. Switch Statement Flow Chart
1st case body
Switch
variable==1st
case constant
Exit
Switch
variable==2nd
case constant
Switch
variable==nth
case constant
2nd case body
Nth case body
Default body
true
true
true
false
false
false

15. Switch Example
#include<iostream>
#include<conio.h>
using namespace std;
int main()
{
char dir=‘a’;
int x=0,y=0;
while(dir!=‘r’)
{
cout<<“Enter your
location”;
dir=getche();
switch(dir)
{
case ‘n’: y--; break;
case ‘s’: y++; break;
case ‘e’: x++; break;
case ‘w’: x--; break;
default: cout<<“try
again”;
} //end switch
}
return 0;
}

16. Conditional Operator ?:
Syntax
result=(Condition)? Expression 1:
Expression 2;

17. Conditional Operator Flow Chart
Expression 1
Test
Expression
Exit
FalseTrue
Expression 2

18. Conditional Operator Example
#include<iostream>
#include<conio.h>
using namespace std;
int main()
{
int x=100, y=0;
int result=(x>y)?x:y;
getche();
return 0;
}

19. Logical Operators
Operator Effect
&& Logical And
|| Logical Or
! Logical Not

20. Logical And
#include<iostream>
#include<conio.h>
using namespace std;
int main()
{
int number;
cout<<“Enter your numbers”;
cin>>number;
if(number>=90)
cout<<“A”;
else if(number>=70 && number<90)
cout<<“B”;
else if(number>=60 && number<70)
cout<<“C”;
else
cout<<“F”;
getche();
return 0;
}

21. Logical Or
#include<iostream>
#include<conio.h>
using namespace std;
int main()
{
char dir=‘a’;
int x=0,y=0;
while(dir!=‘r’)
{
cout<<“Enter your
location”;
dir=getche();
if(dir==‘n’ || dir==‘N’)
y--;
else if(dir==‘s’ ||
dir==‘S’)
y++;
else if(dir==‘e’ ||
dir==‘E’)
x++;
else if(dir==‘w’ ||
dir==‘W’)
x--;
}
return 0;
}

22. Logical Not
#include<iostream>
#include<conio.h>
int main()
{
int x;
cout<<“enter a number”;
cin>>x;
if(!(x==0))
cout<<“Number is not zero”;
getche();
return 0;
}

23. Operator Precedence
Operator Type Operators
Unary !,++,--
Arithmetic *, /, %
+, -
Relational <, >, <=, >=
==, !=
Logical &&
||
Conditional ?:
Assignment =, +=, -=, *=, /=, %=

24. Continue Statement
Condition
within loop
continue;
Start of loop
Normal loop return

25. Example
#include<iostream>
#include<conio.h>
int main()
{
int dividend, divisor;
char ch=‘a’;
while(ch!=‘r’)
{
cout<<“Enter dividend”;
cin>>dividend;
cout<<“Enter divisor”;
cin>>divisor;
if(divisor==0)
continue;
cout<<“Quotient=“<<dividend/divisor;
}
getche();
return 0;
}

26. goto Statement
Syntax
goto Label;
//other statements
Label:
//control will begin here