By Senem Kumova Metin 1 DATA TYPES. by Senem Kumova Metin 2 DATA TYPE? …… x; // DECLARATION OF VARIABLE X printf(“Do you want to go on? \n”) printf(“Please

$Page 1: By Senem Kumova Metin 1 DATA TYPES. by Senem Kumova Metin 2 DATA TYPE? …… x; // DECLARATION OF VARIABLE X printf(“Do you want to go on? \n”) printf(“Please$
by Senem Kumova Metin 1

DATADATA TYPESTYPES


DATA TYPE?DATA TYPE?

…… x; // DECLARATION OF VARIABLE X

printf(“Do you want to go on? \n”)printf(“Please type Y for YES / N for NO”);

scanf(“…….”, &x);


WHAT IS THE APPROPRIATE TYPE ?WHAT IS THE APPROPRIATE TYPE ?

….. x;

printf(“Please make your choise”);printf(“1 Addition\n”);printf(“2 Subtraction\n”);printf(“3 Division\n”);

scanf(“…..”, &x);…..



….. x;…… y;…… result;

printf(“Please give two numbers to divide”);scanf(“…..”, &x);scanf(“…..”,&y);

result= ……. x/y;

printf(“Result of division is …” , result);



…………..printf(“Please write your name and surname”);

scanf(“…..”, name);scanf(“…..”, surname);

printf(“your name is …..”, name);printf(“your surname is …..”,surname);


FLOW OF FLOW OF CONTROLCONTROL

IF STATEMENTIF STATEMENTSWITCH STATEMENTSWITCH STATEMENT

LOOPSLOOPS


FILL IN THE BLANKS FILL IN THE BLANKS int x; int y;

printf(“Please enter 2 numbers to compare”);

scanf(“%d”,&x);scanf(“%d”,&y);…….……


FILL IN THE BLANKS FILL IN THE BLANKS int x;

printf(“Please make your choise”);printf(“1 Addition\n”);printf(“2 Subtraction\n”);printf(“3 Division\n”);scanf(“ %d”, &x);…….…….


FILL IN THE BLANKS FILL IN THE BLANKS int x;int result =0;…….

printf(“Please enter 10 numbers to sum”);

……….……….……….

printf(“Result is %d”,result);


FUNCTIONSFUNCTIONSREVIEWREVIEW


return_type function_name (input_parameter_list){

declarations /* body of the function */ statements

return ……}

return_type : * Zero or one data type ( int, char, float etc.) * “void” keyword can be used if there is no return value * Write the type of the return variable…

input_parameter_list : * Zero or more variables (as int x, float c etc.) * If more than one input parameter exist, then

put commas between them * If there is no parameter, “void” keyword

can be used

FUNCTIONSFUNCTIONS


FUNCTION :EXAMPLE1FUNCTION :EXAMPLE1double twice (double x) /*header=declaration*/

{ /* body starts here */return x*2;}

/* double twice (double x) output input parameter parameters

this function is called “twice()”, it will return a data of type double,

it gets an input data of type double

*/


FUNCTIONFUNCTION :EXAMPLE2:EXAMPLE2• If there is no return value, use “void”

keyword as an output parameter

• If there is no input parameter, use “void” as an input parameter or do not write anything

void menu(void){

printf(“ A\n ”);printf(“ B\n ”);printf(“ C\n ”);

}

void menu() {

printf(“ A\n ”);printf(“ B\n ”);printf(“ C\n ”);

}


FUNCTION :EXAMPLE3FUNCTION :EXAMPLE3

int add1( int x, int y) { return x+y; }

int add2( int x, int y) { int result;

// local variables can be // declared in functionsresult =x+y;return result; }


FUNCTION :EXAMPLE4FUNCTION :EXAMPLE4

int sum( int a, int b) { /* If-else, for, while, do while etc.

statements can be used in functions */int i; int s=0;

for (i=a;i<b;i++)s=s+i;

return s;}


Return statementReturn statement• The return statement may or may not include an

expression

• The return statement terminates the execution of the function, and closes memory space opened for all local variables (kills all local variables of function)

EXAMPLE:

float f(int a, char b){ int i;

….. return i; /* value of i will be converted to float */

/* return (i); */ /* return value can also be written in

braces */}


return statement : return statement : EXAMPLES EXAMPLES

char func1( int a, int b){ return a+b; }

double my_sqrt( int a ){ return sqrt(a); }

int my_max1( int y, int z) { return y>z? y:z ; }

int my_max2 (int y , int z, int t, int x) { int a, b;

a= my_max1(y,z); b=my_max1(t,x);

return my_max1(a,b); }

1 2

3

4

Functions can call other functions


FUNCTION PROTOTYPESFUNCTION PROTOTYPES

• Each function has to be declared before it is used

• There are two ways to achieve this rule ..

– Define the functions before used

– Write the function prototype of the function before used ( Just declaration not definition)

• Function prototype includes header information :– Return type– Function name– Input parameter list


FUNCTION PROTOTYPES : FUNCTION PROTOTYPES : EXAMPLES EXAMPLES

char func1( int a, int b, int c);double func2( char a );

int func3( int y[], int z);

int funct4(int y[] , char z[], int t, int x);

1 2

3

4


Function Definition OrderFunction Definition OrderEXAMPLE 1:

#include<stdio.h>int func_2(); int func_1(); int func_3();

void main(void){ func_1(); func_2(); func_3(); }

int func_2(){…}; int func_1(){…}; int func_3(){…};

EXAMPLE 2: #include<stdio.h>int func_2();

int func_1() { func_3(); }

int func_3();

void main(void){ func_2(); func_1(); }

int func_2(){…};int func_3(){…};


CALL BY VALUECALL BY VALUEIf a variable is passed to a function, the stored value in the calling environment will not be changed!!!

void my_increment (int n){ n=n+1; }

void main(void){ int n=9;

printf(“%d\n” ,n);

my_increment(n); // call function my_increment() // by value


}


CALL BY REFERENCECALL BY REFERENCEIf a variable’s address is passed to a function, the stored value in the calling environment may be changed!!!

void my_increment (int * n){ *n=*n+1; }

void main(void){ int n=9;


my_increment(&n); // call function my_increment()// by value


}


RECURSIONRECURSION• An algorithmic technique where a function, in order

to accomplish a task, calls itself with some part of the task

• If a function calls itself , then it is called recursive !!!

• There are two parts to the definition of a recursive solution:

– Base case: Simple, non-recursive solution

– General method: Uses simpler version of the problem to solve harder problem


RECURSION EXAMPLE 1RECURSION EXAMPLE 1

// ITERATIONint sum(int N) { int i;

int SUM =0;

for (i=1; i<=N; i++)

SUM=SUM+i;

return SUM; }

// RECURSIONint sum(int N){ if(N==1) return 1;

else return(N+sum(N-1)); }

/* BASE CASE : N==1 1METHOD : sum(N) = N + sum(N-1)

if BASE CASEelse METHOD

*/

)()1(.......43211

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RECURSION EXAMPLE 2RECURSION EXAMPLE 2

BASE CASE N=1 return 1METHOD sum(N)= sum(N-1)+1/N

double sum(int N){ if(N==1) return 1;

else return (sum(N-1)+1/N); }

)(11

1

1.......

4

1

3

1

2

1

1

1

1

NsumiNN

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RECURSION vs ITERATIONRECURSION vs ITERATION

Iteration in computing is the repetition of a process within a computer program

Recursion is a method of defining functions in which the function being defined is applied within its own definition


EXAMPLE: EXAMPLE: RECURSION & ITERATIONRECURSION & ITERATION

• Write a function that prints numbers from 1 to N using iteration

• Convert your function to work in a recursive way

void main( )

{ print(5); } // 1 2 3 4 5


/* ITERATION */void print( int N){ int i;

for (i=1;i<=N;i++)printf(“%d\t”,i);

}

/* RECURSION*/void print( int N){

if(N==1) printf(“1\t”);else { print(N-1);

printf(“%d\t”,N);}

}


FACTORIAL EXAMPLE: FACTORIAL EXAMPLE: RECURSION & ITERATIONRECURSION & ITERATION

/* iterative version

n! = 1*2*3* … * n

= n*(n-1)*(n-2) * …*3*2*1

*/

int factorial (int n)

{ int product = 1;

for(;n>1;--n)

product = product*n;

return product; }

/* recursive version

n! = n * (n-1)! */

int factorial(int n)

{ if(n<=1) return 1;

else return ( n*factorial(n-1));

}

/* BASE CASE : n<=1 1

METHOD : n!=n*(n-1)! */

factorial(3) = 3 * factorial(2) = 3 * ( 2 * factorial(1) ) = 3 * ( 2 * ( 1 * factorial(0) )) = 3 * ( 2 * ( 1 * 1 ) )) = 6

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By Senem Kumova Metin 1 DATA TYPES. by Senem Kumova Metin 2 DATA TYPE? …… x; // DECLARATION OF VARIABLE X printf(“Do you want to go on? \n”) printf(“Please