Programming for Problem Solving Unit 2

CSEG1003 Programming for Problem Solving

CSEG 1001
Computer Programming
Instructor
Dhiviya Rose J . Asst. Prof. Senior Scale
School of Computer Science and Engineering | UPES
CSEG1003 Programming for Problem
Solving

Road Map
• Generations of Computers and Languages
• Organization of Computers-Online Lecture
• Number Systems Conversion
• Logical Analysis and Thinking
Introduction to
Computers
• Structure of C Program & Compilation and Linking Process
• Variables and Datatypes
• Managing Input and Output statements and Operators
• Decision and Looping Statements
C Programming
Basics
• Creation and Usages
• 1D and 2 D arrys
• String Functions
• Matrix operations
Arrays and
Strings
• Declaration and Definitions of Functions
• Passing Arguments
• Recursion
• Pointers & Pointer Arithmetic
Functions and
Pointers
• Need of Structure and Unions
• Declaration and Definition
• Storage classes
• Preprocessor Directives
Structures and
Unions
Solving

Online Lecture
• Problem Formulation
• Problem Solving
• Introduction to C
Solving

LECTURE #8
STRUCTURE OF C PROGRAM ..COMPILATIONAND
LINKING
Instructor
Solving

Structured Blocks -> Functions
• Solves a large problem
• divides the problem into smaller
modules called functions
• each have particular responsibility.
• The program which solves the
entire problem is a collection of
such functions.
• Types
• Built-in Functions (Predefined)
• E.g. printf(), scanf()
• User-defined Functions
Solving

Example Program 1
#include<stdio.h>
void main()
{
printf("Hello");
printf("this is my function");
}
9Instructor: Dhiviya Rose J , AP-Sr. Scale | CIT

Example Program 2
#include<stdio.h> PREPROCESSOR DIRECTIVE
void myline(); FUNCTION DECLARATION
void main()
{
printf("Hello");
myline(); FUNCTION CALL
}
void myline()
{
printf("this is my function"); FUNCTION DEFINITION
}
10Instructor: Dhiviya Rose J , AP-Sr. Scale | CIT

Functions Example 3
Solving
OUTPUT ?????
Function Call ????
Function definition???
Function Declaration????

Main Function
Solving
• When system is executed it calls the main function
• Entry point of any program
• Can have void main(){……}
• where it return type is void
• Or can be int main(){……… return 0;}
• where it returns an integer.

Steps in C compilation

Files in a C program
Solving
Binary Format
a.out ./ <obj file>

Structure
of
C
Program
Solving

Documentation
• Comments
• provide clarity to the C source code and allows others to better
understand
• helps in debugging the code.
• Two types
• Single Line //
• Multiline /* any text */
// This is my first Program
/* Written for Engineering students of Petroleum University for the batch
2018-1019 students */
#include <stdio.h>
void main()
{
printf(“Hello”);
}
Solving

Preprocessing
• First stage of compilation
• Lines starting with a # character are interpreted by the
preprocessor as preprocessor commands.
• This language is used to reduce repetition in source code
• Print the result of the preprocessing stage, pass the -E
option to gcc:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
Solving

Solving

LECTURE #9
VARIABLES, CONSTANTS, DATATYPESAND
OPERATORS
Instructor
Solving

Knowledge Checks
#include <stdio.h>
void solveMeFirst( )
{
int num1,num2;
scanf("%d %d",&num1,&num2);
int sum;
sum = num1+num2;
printf("%d",sum);
}
void main()
{
________________Fill me
}
Solving

Knowledge Check
• C Program Specification
• 3 user defined functions
• F1 -> prints “I am F1”
• Required Output
I am F2
I am F3
I am F1
I am F2
Solving

Keywords
• C has a set of 32 reserved words often known as
keywords.
• All keywords are basically a sequence of characters
that have a fixed meaning.
• By convention all keywords must be written in
lowercase (small) letters.
• Example: for, while, do-while, auto break, case, char,
continue, do, double, else, enum, extern, float, goto,
if, int, long, register, return, short, signed, sizeof,
static, struct, switch, typedef, union, unsigned, void,
volatile
Solving

Identifiers
• Identifiers are names given to program elements such as
variables, arrays and functions.
• Rules for forming identifier name
• it cannot include any special characters or punctuation marks (like #,
$, ^, ?, ., etc) except the underscore"_".
• There cannot be two successive underscores
• Keywords cannot be used as identifiers
• The names are case sensitive. So, example, “FIRST” is different from
“first” and “First”.
• It must begin with an alphabet or an underscore.
• It can be of any reasonable length. Though it should not contain more
than 31 characters.
• Example: roll_number, marks, name, SAP_ID, COURSE,
SEM
Solving

Variables
• Meaningful name given to the data storage location in
computer memory.
• C language supports two basic kinds of variables.
• Numeric variables can be used to store either integer values or
floating point values.
• While an integer value is a whole numbers without a fraction part or
decimal point, a floating point number, can have a decimal point in
them.
• Numeric values may also be associated with modifiers like short, long,
signed and unsigned.
• By default, C automatically a numeric variable signed..
• Character variables can include any letter from the alphabet or from
the ASCII chart and numbers 0 – 9 that are put between single
quotes.
Solving

Data & Variable
Solving

Knowledge Check - Output????
Solving

DataType in C language
Solving

Variable Declaration / Definition
• Declaring/Definition a Variable
• Declaration announces the data type of a variable and allocates
appropriate memory location.
• Each variable used must be declared.
• A form of a declaration statement is
data-type var1, var2,…;
Examples
int sum = 0;
char t1 = ‘a’;
float epsilon = 1.44;
Solving

Possible ways of Variable Declaration
Solving

Know your datatype char….
Solving

Range of Datatypes in C

Global and Local Variables
• Global Variables
• These variables are
declared outside all
functions.
• Life time of a global
variable is the entire
execution period of the
program.
• Can be accessed by any
function defined below the
declaration, in a file.
• Local Variables
• These variables are
declared inside some
functions.
• Life time of a local
variable is the entire
execution period of the
function in which it is
defined.
• Cannot be accessed by any
other function.
• In general variables
declared inside a block are
accessible only in that
block.

Example

Constants
• Constants are identifiers whose value does not
change.
• To declare a constant, precede the normal variable
declaration with const keyword and assign it a value.
For example,
const float pi = 3.14;
• Another way to designate a constant is to use the pre-
processor command define.
#define PI 3.14159
Solving

Operators in C
• C language supports a lot of operators to be used in
expressions. Includes
• Arithmetic operators
• Relational Operators
• Equality Operators
• Logical Operators
• Unary Operators
• Conditional Operators
• Bitwise Operators
• Assignment operators
• Comma Operator
• Sizeof Operator
Solving

Arithmetic and Relational
Solving

Logical and Unary
• Logical operators
• Logical AND (&&)
• Logical OR (||)
• Logical NOT (!).
• As in case of arithmetic expressions, the logical
expressions are evaluated from left to right.
• Unary operators
• act on single operands.
• Three unary operators
• unary minus(-)
• Increment(++)
• Decrement operators(--)
Solving

Conditional Operator
• (?:) is just like an if .. else statement
• Syntax of the conditional operator is
exp1 ? exp2 : exp3
• Eg.
large = ( a > b) ? a : b
• Conditional operator is also known as ternary
operator as it is neither a unary nor a binary operator;
it takes three operands.
Solving

Bitwise and Bitwise Shift Operators
• Bitwise operators perform operations at bit level.
• bitwise AND operator (&)
• bitwise OR operator (|)
• bitwise NOT (~)
• bitwise XOR operator (^)
• In bitwise shift operations, the digits are moved, or shifted,
to the left or right.
• Left Shift unsigned (<<)
int x = 11000101;
x << 2 = 00010100
• Right arithmetic shift (>>)
int x = 11000101;
x >> 2 = 00110001
Solving

Assignment, Comma Operator
Solving
equal sign (=) is the fundamental assignment operator, C also supports
other assignment operators that provide shorthand ways to represent
common variable assignments.
Comma separated operands when chained together are evaluated in left-
to-right sequence with the right-most value yielding the result of the
expression.

Sizeof operator
• sizeof is a unary operator used to calculate the sizes
of data types.
• sizeof(char) returns 1, that is the size of a character
data type.
int a = 10;
int result;
result = sizeof(a);
then result = 2,
Solving

LECTURE #10
INPUTAND OUTPUT STATEMENTS
Instructor
Solving

OUTPUT STATEMENT - printf()
• printf() function
• Output to Standard Output
• Prototype definition available in stdio.h

• Case 1: printing only text
Flowchart code Output
printf(“Hello”); Hello
• Case 2: printing only value of a variable
printf(“%d” , area); 120
• Case 3: printing text and a value
printf(“The value of area is %d”,area); The value of area is 120
Print Hello
Print area
OUTPUT STATEMENT - printf()
Solving

INPUT STATEMENT – scanf()
• Case 1: getting 1 input value
scanf( “%d”, &r);
scanf( “%d %d ”, &l, &b);
scanf( “%d %d %d ”, &a, &b ,&c);
Solving

• scanf() function
• Input from Standard Input
• Prototype definition available in stdio.h
• Format Specifier(%d)
• Address-of Operator (&)
• Provides the memory address of the input variable were the input value is to
be stored

DECISION STRUCTURES IN C
Solving

List of Decision Making Structures in C
•If structure
•If Else structure
•Nested If structure
•Switch Structures
•Conditional Operator/
Terniary operator
Solving

Converting a if block to C program
Solving
if(condition)
{
//true statements
}

Check if entered number is positive
Solving

Converting a if-else block to C program
Solving
if(condition)
{
//true statements
}
else
{
//false statements
}

Example: If Else Statement
Solving

Knowledge Checks – Implement – If… Else
Solving

Nested IF
Solving
if(condition 1)
{
//true statements
}
else if(condition 2)
{
//statements
}
else if(condition 3)
{
//statements
}
else
{
//statements
}

Example
Solving

switch …case decision Implementation
Solving

Switch Case
• Keywords used switch, case, default, break
• An value is passed as the input
• Switch(value)
• Evaluates with an value in each case
• Case 1:
• Case ‘A’:
• Default:
• Break is used to get exit from switch block
• Break;
Solving

Convert Switch to C program
Solving

Switch case Vs Nested IF
Solving

Knowledge Check
Solving

Knowledge Checks
Solving

EXPERIMENT NO – 4
Control Statements in C Language
List of lab works:
1. Write a program to accept 3 numbers and find the greatest of them, using
if…….else statements.
2. Write a program to find the biggest of 3 numbers using conditional operator/ternary
operator?
3. Write a program to check whether the roots of a quadratic equation are real or
imaginary?
4. Program to find the average of students marks, if average<50 then result is ‘FAIL’
otherwise print the grade as pass /first class/distinction.
5. A book and stationary store decides to give its customers 10% discount on a
purchase greater than 10,000/-. The program should accept the quantity
purchased the price of the items and then calculate the amount payable. Further
based on the total amount, appropriate discount should be given and final payable
amount should be displayed.
6. Write a program to accept a number and display “Sunday/Monday/Tuesday…..”
Based on the number. (hint: if 1 is input then “Sunday”, if 2 is input then
“Monday”…..) using switch case.
7. Read the minutes from the keyboard and find out the no. of hours, mins , days ?
(Ex 1210 mins are displayed as 0 days,20 hrs,10 min)
Solving

LECTURE #13
LOOP STRUCTURES IN C
Instructor
Solving

Introduction - Loop Statements
• Helps in executing a statement in flowchart repeatedly
• Loop statements – block of statement executed more
than one time
• How many times the loop statements are executed is
managed by a counter variable
• Counter Variable Initialization
• Eg. C=0
• Counter Variable Increment/Decrement
• Eg. C++, c=c+1,c=c+3
• Counter Variable Condition Check
• Eg. C<3
Solving

List of Loop Structures in C
• While
• Do….While
• For
Solving

While
• Entry condition check loop
Solving

Example – While Program
Solving

Do … While Loop
• Exit check Loop
• At least executes the
statement once
if the condition is false
Solving

At least executes once - if condition fails
Solving

For
Solving

Continue statement
Solving

EXPERIMENT NO – 5
Loop Statements in C Language
List of lab works:
1. Write a program to print half pyramid using *.
2. Write a C program to print all natural numbers from 1-n
using while loop.
3. Write a C program to find the sum of all even numbers
between 1 to n using do-while loop.
4. Write a C program to print multiplication table of any
number using for loop.
Solving

KNOWLEDGE CHECKS
Input – Output Statements
Solving

1. I = scanf("%d%d",&a,&b); value of I will be
2. I = sizeof(float); the value of I will be
3. i=printf("%d",20000); then i=?
4. i=printf("upes"); then i= ?
5. i=scanf("%d",&a); then i=?
Solving

6. i=printf("%d",20000); then i=?
7. printf("%d",printf("%d",345)); the output of the
statement will be ?
8. printf(“%d”,’A’);
9. printf("%o",12); the output of the statement will be ?
10. printf("%d",2&2); the output of the statement will
be ?
11. printf("%.2f",78.34567);
Solving

KNOWLEDGE CHECKS
Conditional and Loop Statements
Solving

Question 1
#include <stdio.h>
int main()
{
int var=100;
{
int var=200;
printf("%d...",var);
}
printf("%d",var);
return 0;
}

Question 2
int main()
{
int n,i=0;
while(scanf("%d",&n)==1)
{
printf("ENDn");
break;
}
return 0;
}

Question 3
int main()
{
int n=10,i=0;
while(1)
{
printf("ENDn"); n++;
}
return 0;
}

Question 4
int a=2;
switch(a)
{
case 1:
printf(“one ”);
case 2:
printf(“two ”);
case 3:
printf(“three ”);
default:
printf(“other ”);
}

Question 5
void anyFun(int a)
{
if(a==0)
return;
printf("Value is not Zero.");
}
void main()
{
anyFun(0);
}

Question 6
#include <stdio.h>
void fun(int a,int b)
{
a+=10;
b+=10;
}
int main()
{
int val1=10;
int val2=10;
printf("nValue before function calling : %d, %d",val1,val2);
fun(val1,val2);
printf("nValue after function calling : %d, %d",val1,val2);
return 0;
}

Question 7
#include <stdio.h>
void fun1(void)
{
void fun2(void); /*another function declaration*/
printf("nI am fun1");
fun2();
}
int main()
{
fun1();
return 0;
}
void fun2(void)
{
printf("nI am fun2");
}

Question 8
for(i=1;i<=2;i++)
{
for(j=1;j<=10;j++)
{
printf("%d ",j);
}
printf("n");
}

Programming for Problem Solving Unit 2

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