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INSTRUCTOR:
ENGR. AFSHAN ASIM
CHAPTER # 3
LOOPS & DECISIONS
OBJECTIVES
• Relational operators.
• For Loop
• While Loop
• do while Loop
• Nested Loop
RELATIONAL OPERATORS
Operator Meaning
> Greater than
< Less than
== Equal to
!= Not equal to
>= Greater than or equal to
<...
RELATIONAL OPERATORS (CONTD…)
int a=12; //assignment statement
int b=34; //assignment statement
(b<34) //false or 0
(b<=34...
LOOPS
• Three kinds of loops
• For
• While
• Do-while
FOR LOOP
Syntax
•Single Statement Loop
for(variable initialization, condition, variable update)
statement; //executed if c...
FOR LOOP FLOW CHART
Initialization
Expression
Body of Loop
Increment
Expression
Test
Expression
Exit
false
True
FOR LOOP EXAMPLE
//single statement loop
#include<iostream>
using namespace std;
void main()
{
int i;
for(i=0;i<10;i++)
co...
FOR LOOP EXAMPLE
//multi statement loop
#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
int i;
for(...
BLOCK & VARIABLE VISIBILITY
//multi statement loop
#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
...
FOR LOOP VARIATIONS
//increment expression variations
#include<iostream>
using namespace std;
int main()
{
int i;
for(i=10...
FOR LOOP VARIATIONS
//variables defined in for statement
#include<iostream>
using namespace std;
int main()
{
for(int i=0;...
FOR LOOP VARIATIONS
//multiple initialization and increment
expressions
#include<iostream>
using namespace std;
int main()...
TASK
What happens if you use for loop in the
following manner
•for(;;)
•for(;;);
(Submit your answers in the next class)
WHILE LOOP
Syntax
•Single Statement while Loop
while(test expression)
statement;
•Multi Statement while Loop
while(test ex...
WHILE LOOP FLOW CHART
Body of Loop
Test
Expression
Exit
false
True
WHILE LOOP EXAMPLE
#include<iostream>
using namespace std;
int main()
{
int i=0;
while(i<10)
{
cout<<i<<endl;
i++;
}
syste...
DO WHILE LOOP
Syntax
do
{
Body of loop
}
while(test expression);
DO WHILE LOOP FLOW CHART
Body of Loop
Test
Expression
Exit
false
True
DO WHILE LOOP EXAMPLE
#include<iostream>
using namespace std;
int main()
{
int i=0;
do
{
cout<<i<<endl;
i++;
} while(i<10)...
NESTED LOOPS
• Loops inside another loop
• Example
for(int i=0;i<3;i++)
{
for(int j=0;j<3;j++)
{
cout<<“Loop2”;
}
cout<<“n...
NESTED LOOPS EXAMPLE
• Program to print the following
pattern
*
* *
* * *
* * * *
CONTD…
#include<iostream>
using namespace std;
int main()
{
int num=1;
for(int i=0;i<4;i++)
{
for(int j=0;j<num;j++)
{
cou...
c++ Lecture 3
c++ Lecture 3
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c++ Lecture 3

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c++ Lecture 3

  1. 1. INSTRUCTOR: ENGR. AFSHAN ASIM CHAPTER # 3 LOOPS & DECISIONS
  2. 2. OBJECTIVES • Relational operators. • For Loop • While Loop • do while Loop • Nested Loop
  3. 3. RELATIONAL OPERATORS Operator Meaning > Greater than < Less than == Equal to != Not equal to >= Greater than or equal to <= Less than or equal to
  4. 4. RELATIONAL OPERATORS (CONTD…) int a=12; //assignment statement int b=34; //assignment statement (b<34) //false or 0 (b<=34) //true or 1 (a==12) //true or 1 (b!=35) //true or 1 (a>14) //false or 0 (a>=10) //true or 1
  5. 5. LOOPS • Three kinds of loops • For • While • Do-while
  6. 6. FOR LOOP Syntax •Single Statement Loop for(variable initialization, condition, variable update) statement; //executed if condition true •Multi Statement Loop for(variable initialization, condition, variable update) { //executed if condition true statement1; statement2; }
  7. 7. FOR LOOP FLOW CHART Initialization Expression Body of Loop Increment Expression Test Expression Exit false True
  8. 8. FOR LOOP EXAMPLE //single statement loop #include<iostream> using namespace std; void main() { int i; for(i=0;i<10;i++) cout<<i<<endl; system(“pause”); }
  9. 9. FOR LOOP EXAMPLE //multi statement loop #include<iostream> #include<iomanip> using namespace std; int main() { int i; for(i=0;i<10;i+=2) { //loop body starts cout<<setw(4)<<i; int j=i*i*i; cout<<setw(6)<<j<<endl; } //loop body ends system(“pause”); }
  10. 10. BLOCK & VARIABLE VISIBILITY //multi statement loop #include<iostream> #include<iomanip> using namespace std; int main() { int i; for(i=0;i<10;i++) { //loop body starts cout<<setw(4)<<I; int j=i*i*i; cout<<setw(6)<<j<<endl; } //loop body ends cout<<j; //ERROR system(“pause”); }
  11. 11. FOR LOOP VARIATIONS //increment expression variations #include<iostream> using namespace std; int main() { int i; for(i=10;i>0;i--) { //loop body starts cout<<i; cout<<endl; } //loop body ends system(“pause”); }
  12. 12. FOR LOOP VARIATIONS //variables defined in for statement #include<iostream> using namespace std; int main() { for(int i=0;i<10;i++) { //loop body starts cout<<i; cout<<endl; } //loop body ends system(“pause”); }
  13. 13. FOR LOOP VARIATIONS //multiple initialization and increment expressions #include<iostream> using namespace std; int main() { int i; for(i=0,alpha=100;i<10;i++,alpha--) { //loop body starts …….. cout<<i; cout<<endl; } //loop body ends system(“pause”); }
  14. 14. TASK What happens if you use for loop in the following manner •for(;;) •for(;;); (Submit your answers in the next class)
  15. 15. WHILE LOOP Syntax •Single Statement while Loop while(test expression) statement; •Multi Statement while Loop while(test expression) { Body of loop }
  16. 16. WHILE LOOP FLOW CHART Body of Loop Test Expression Exit false True
  17. 17. WHILE LOOP EXAMPLE #include<iostream> using namespace std; int main() { int i=0; while(i<10) { cout<<i<<endl; i++; } system(“pause”); }
  18. 18. DO WHILE LOOP Syntax do { Body of loop } while(test expression);
  19. 19. DO WHILE LOOP FLOW CHART Body of Loop Test Expression Exit false True
  20. 20. DO WHILE LOOP EXAMPLE #include<iostream> using namespace std; int main() { int i=0; do { cout<<i<<endl; i++; } while(i<10); system(“pause”); }
  21. 21. NESTED LOOPS • Loops inside another loop • Example for(int i=0;i<3;i++) { for(int j=0;j<3;j++) { cout<<“Loop2”; } cout<<“nLoop1 “; } Inner Outer
  22. 22. NESTED LOOPS EXAMPLE • Program to print the following pattern * * * * * * * * * *
  23. 23. CONTD… #include<iostream> using namespace std; int main() { int num=1; for(int i=0;i<4;i++) { for(int j=0;j<num;j++) { cout<<“*”; } num++; cout<<endl; } system(“pause”); }

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