Controln Loops Cont

7/29/2019 Controln Loops Cont

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20-01-03 P.P.Chakrabarti, IIT Kharagpur 1

Control & Loops continued

P. P. Chakrabarti


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else if statements

if (expression)

statement

else if (expression)

statement

else if (expression)

statementelse

statement

if (x%4 == 0)

sum += 2;

else if (x%4 == 1)

sum *= 2;

else if (x%4 == 2)

sum--;

else if (x%4 == 3)

sum++;

else

sum += 4;


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switch

switch (expression) {

case const-expr/: statements

caseconst-expr

/:statements

default : statements

}

switch (choice = getchar()) {

case r :

case R: printf(Red);

break;

case b :

case B : printf(Blue);

break;

case g :

case G: printf(Green);

break;

default: printf(Black);

}


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int main () {

int operand1, operand2;

int result = 0;char operation ;

/* Get the input values */

printf (Enter operand1 :);

scanf(%d,&operand1) ;printf (Enter operation :);

scanf (\n%c,&operation);

printf (Enter operand 2 :);

scanf (%d, &operand2);

switch (operation) {case + :

result=operand1+operand2;

break;


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case - :

result=operand1-operand2;

break;case * :

result=operand1*operand2;

break;

case / :

if (operand2 !=0)result=operand1/operand2;

else

printf(Divide by 0 error);

break;

default:printf(Invalid operation\n);

}

printf (The answer is %d\n,result);

}


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Math functions

#include

int main()

{ float x,y,z;

scanf(%f, &x);

printf(tan(asine(%f/2)) = %f \n, x, tan(asine(x/2.0)));

scanf(%f%f%f, &x,&y,&z);

printf(pow(%f, pow(%f, pow(%f, 1.0/3.0))) = %f\n,

x,y,z, pow(x, pow(y, pow (z, 1.0/3.0))));

}

First one is tan(sin-1(x/2))

Guess the second one

compile with lm option


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for loop

for( exp ression1; expression2; exp ression3)statement

expression1 (init) : initialize parameters

expression2 (test): test condition, loop continues ifsatisfied

expression3 (reinit): used to alter the value of theparameters after each iteration

statement (body): body of the loop


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Counting in for loops

for (count=1; count


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for( expression1; expression2; expression3)

statement

expression1;

while (expression2) {

statement

expression3;

}

expression1

(init)

expression2(test)

statement

(body)

expression3

(reinit)

F

T


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Examples : for loop

for (i=0; i


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Computing a series

main ()

{

int i,inp;float x, term=1, sum=0;

scanf(%d%f, &inp,&x);

for (i=1; i


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2-D Figure

Print

* * * * *

* * * * *

* * * * *

#define ROWS 3

#define COLS 5

....

for (row=1; row


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Another 2-D Figure

Print

*

* ** * *

* * * *

* * * * *

#define ROWS 5

....

int row, col;

for (row=1; row


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Some Loop Pitfalls

while (sum


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Use ints as loop counters

int i;

double x;

for (i=0; i


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Some exercises

? Sum= a + (a+d) +(a+2d) + . . . + (a+ (n-1)d)

? The sine of x can be calculated approximately by summing thefirst n terms of the infinite series: x - x3 /3! + x5 /5! x7 /7! + . . .

or upto a given accuracy level, say correct upto 5 decimalplaces. (Here x is in radians.)

? Read an integer and convert to its binary representation. (Findout what a binary representation is).

? Read in a number in its binary representation and print thenumber as an integer.

? Read in a string of characters and print the number of timeseach vowel occurs.

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