This document is a lab report submitted by a student that summarizes different control flow statements in C including if, if else, else if ladder, nested if else, and switch statements. It provides examples of code for each statement. The lab assessment section has the student write programs to find the largest of three numbers, determine a grade based on marks, and check if a number is even or odd using the control flow statements. The conclusion states that the experiment helped the student learn about C control flow.

1. Dhaka University of Engineering & Technology, (DUET) Gazipur
Department of Textile Engineering
Course NO: CSE- 3702
Course Name: Computer Applications and Programming (Sessional)
Date of Submission: 04-04-2021
Experiment No: 03
Name of the Experiment: Introduction to C control flow (if,
if else, else if ladder, nested if else, switch statement)
Submitted To
Mr. Khawja Imran
Masud
Lecturer,
Department of CSE,
DUET
Submitted By
Name: Md. Rasel Mondal
Student ID: 175013
Year/Semester: 3/1
Session: 2019-20
Lab Date: 28-03-2021

2. Report No: 03
Report Name: Introduction to C control flow (if, if else, else if ladder, nested if
else statement, switch statement)
1.0 Objectives:
• To know about C control flow.
2.0 Theory:
2.1 if Statement:
The syntax of the if statement in C programming is:
if (test expression)
{
// code
}
Example:
#include <stdio.h>
int main()
{
int number;
printf("Enter an number: ");
scanf("%d", &number);
if (number >5 )
{
printf("entered number %d.n", number);
}

3. return 0;
}
Output:
2.2 if. else Statement:
The if statement may have an optional else block. The syntax of
the if..else statement is:
if (test expression) {
// run code if test expression is true
}
else {
// run code if test expression is false
}
Example:
#include <stdio.h>
int main()
{
int number;
printf("Enter a number: ");
scanf("%d", &number);

4. if (number%2 == 0)
{
printf("%d is an even integer.",number);
}
else
{
printf("%d is an odd integer.",number);
}
return 0;
}
Output:
2.3 else if ladder Statement:
The if...else statement executes two different codes depending upon whether the
test expression is true or false. Sometimes, a choice has to be made from more than
2 possibilities.

5. The if...else ladder allows you to check between multiple test expressions and
execute different statements.
Syntax of if...else Ladder
if (test expression1) {
// statement(s)
}
else if(test expression2) {
// statement(s)
}
else if (test expression3) {
// statement(s)
}
.
.
else {
// statement(s)
}
Example:
#include <stdio.h>
int main ()
{
int number;
scanf("%d", &number);
if(number>= 80)
{

6. printf("Grade: A pluse");
}
else if(number>=75 && number<80)
{
printf("Grade: A Regular");
}
else
{
printf("Grade: Fail");
}
return 0;
}
Output:
2.4 nested if else Statement:

7. This program given below relates two integers using either <, > and = similar to
the if...else ladder's example. However, we will use a nested if...else statement to
solve this problem.
#include<stdio.h>
int main()
{
int num=1;
if(num<10)
{
if(num==1)
{
printf("The value is:%dn",num);
}
else
{
printf("The value is greater than 1");
}
}
else
{
printf("The value is greater than 10");
}
return 0;
}

8. Output:
2.5 switch Statement:
A switch statement allows a variable to be tested for equality against a list of values.
Each value is called a case, and the variable being switched on is checked for
each switch case.
Syntax
The syntax for a switch statement in C programming language is as follows
switch(expression) {
case constant-expression :
statement(s);
break; /* optional */
case constant-expression :
statement(s);
break; /* optional */
/* you can have any number of case statements */
default : /* Optional */
statement(s);
}
Example:
#include <stdio.h>

9. int main()
{
int num = 8;
switch (num)
{
case 7:
printf("Value is 7");
break;
case 8:
printf("Value is 8");
break;
case 9:
printf("Value is 9");
break;
default:
printf("Out of range");
break;
}
return 0;
}
Output:

10. 3.0 Lab assessment:
3.1 Write a C program to find the largest number among three
numbers.
#include<stdio.h>
int main()
{
int a=20, b=30, c=10;
if(a>b)
{
if(a>c)
printf("a is the largest:%d",a);
else
printf("c is the largest: %d",c);
}
else
{
if(c>b)
printf("c is the largest:%d",c);
else
printf("b is the largest:%d",b);
}

11. return 0;
}
Output:
3.2 Write a C program to find grade of marks.
#include<stdio.h>
int main ()
{
int marks;
scanf("%d", &marks);
if(marks>= 80)
{
printf("Grade: A pluse");
}
else if(marks>=75 && marks<80)
{
printf("Grade: A Regular");
}
else if (marks>=70 && marks< 75)
{
printf("Grade: A Minus");
}
else if(marks>=65 && marks< 70)
{

12. printf("Grade: B Plus");
}
else if(marks>=60 && marks< 65)
{
printf("Grade: B Regular");
}
else if( marks>= 55 && marks< 60)
{
printf("Grade: B Minus");
}
else
{
printf("Grade: Fail");
}
return 0;
}
Output:
3.3 Write a c program to check whether a number is even or odd.
#include<stdio.h>
int main()
{
int num;
scanf("%d", &num);

13. if(num%3==0)
{
printf("Number %d is even",num);
}
else
{
printf("Number %d is odd",num);
}
return 0;
}
Output:
4.0 Conclusion:
In this Experiment we know about C control flow (if, if else, else if ladder, nested
if else, switch statement. I hope this experiment will help in my practical life.