while loops

while loopswhile ( <expression> ){

<statements>}

--------------------------

while ( <expression> )<simple statement> ;

while loops - examplex = 7;while ( x < 10 ){

printf("%d",x);x++;

}

OUTPUT:

while loops - examplex = 7;while ( x < 3 ){

printf("%d",x);x++;

}

OUTPUT:

do-while loopsdo {

statements} while ( <expression> )

do-while loops - examplex = 7;do {

printf("%d",x);x++;

} while ( x < 10 )

OUTPUT:

do-while loops - examplex = 7;do {

printf("%d",x);x++;

} while ( x < 3 )

OUTPUT:

comparison while vs do-whilex = 7;do {

printf("%d",x);x++;

} while ( x < 10 )

OUTPUT:

x = 7;while ( x < 10 ) {

printf("%d",x);x++;

}

OUTPUT:

comparison while vs do-whilex = 7;do {

printf("%d",x);x++;

} while ( x < 3 )

OUTPUT:

x = 7;while ( x < 3 ) {

printf("%d",x);x++;

}

OUTPUT:

Ideal use for while: when you don't know how many times to loop

OUTPUT:

Change problem - while example

Statement of problem:

Given any amount of change under $2.00, determine and print out the minimum number of coins required to make that amount of change. Available coins are Halves, Quarters, Dimes, Nickels, and Pennies.

Flowcharting

Process

Predefined Process

Preparation

Decision

User Input

Input/Output

Display Output

Terminator

Connector

Connector (off page)

Flowcharting - Sample

myAmt = amount

myAmt < 0.50

scanf amount

Start

printf nHalves

Given some amount of money, amount, how many half dollars would be returned?

myAmt = myAmt - 0.50

nHalves = nHalves + 1

nHalves = 0

Finish

Expand to all coins - page 1

myAmt < 0.50

myAmt = myAmt - 0.50

nH = nH+ 1

myAmt = amount

scanf amount

Start nH = 0

A

A

B

myAmt < 0.25

myAmt = myAmt - 0.25

nQ = nQ + 1

nQ = 0

C

myAmt < 0.10

myAmt = myAmt - 0.10

nD = nD + 1

nD = 0

myAmt < 0.05

myAmt = myAmt - 0.05

nN = nN + 1

nN = 0

C

myAmt < 0.01

myAmt = myAmt - 0.01

nP = nP + 1

nP = 0

B

D

D

printf nH,nQ,nD,nN,nP

Finish

Expand to all coins - page 1

myAmt < vH

myAmt = myAmt - vH

nH = nH+ 1

myAmt = amount

scanf amount

Start nH = 0; vH=0.50

A

A

B

myAmt < vQ

myAmt = myAmt - vQ

nQ = nQ + 1

nQ = 0; vQ=0.25

C

myAmt < vD

myAmt = myAmt - vD

nD = nD + 1

nD = 0; vD=0.10

myAmt < vN

myAmt = myAmt - vN

nN = nN + 1

nN = 0; vN=0.05

C

myAmt < vP

myAmt = myAmt - vP

nP = nP + 1

nP = 0; vP=0.01

B

D

D

printf nH,nQ,nD,nN,nP

Finish

myAmt < vQ

myAmt = myAmt - vQ

nQ = nQ + 1

nQ = 0; vQ=0.25

C

myAmt < vD

myAmt = myAmt - vD

nD = nD + 1

nD = 0; vD=0.10

B

myAmt < vC

myAmt = myAmt - vC

nC = nC + 1

nC = 0; vC=input

General case:

nC=number coins OutputvC=value of coin InputmyAmt=amt left Input/Output

function: change

return

myAmt < vC

myAmt = myAmt - vC

nC = nC + 1

nC = 0; vC=input

General case:

nC=number coins OutputvC=value of coin InputmyAmt=amt left Input/Output

function:change(addr nC, val vC, addr Amt)

return

myAmt = amount

scanf amount

Start

change(nH,vH,myAmt)

change(nQ,vQ,myAmt)

change(nD,vD,myAmt)

change(nN,vN,myAmt)

change(nP,vP,myAmt)

printf nH,nQ,nD,nN,nP

Finish

myAmt < vC

myAmt = myAmt - vC

nC = nC + 1

nC = 0; vC=input

General case:

nC=number coins OutputvC=value of coin InputmyAmt=amt left Input/Output

function:change(addr nC, val vC, addr Amt)

return

myAmt = amount

scanf amount

Start

change(nH,vH,myAmt)change(nQ,vQ,myAmt)change(nD,vD,myAmt)change(nN,vN,myAmt)change(nP,vP,myAmt)

printf nH,nQ,nD,nN,nP

Finish

myAmt < 0

myAmt = amount

scanf amount