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ESc101: Fundamentals of Com utin

2011-12-Monsoon Semester

Lecture #9, August 11, 2011

Please switch off your mobile phones.

Announcements

th

Saturday, 20th August.

Monday lab scheduled on 22nd August will instead be held onSaturday, 27th August.

Lec-09 Dheeraj Sanghi, CSE Dept., IIT Kanpur

ESc101, 2011-12-Monsoon

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Wednesday lab scheduled on 31st August will instead be held

on Saturday, 3rd September.

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Recap

while statement

for statement

Logical operators

Example programs

Lec-09 Dheeraj Sanghi, CSE Dept., IIT Kanpur

ESc101, 2011-12-Monsoon

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Getting out of loop

One can get out of loop without checking condition to be false,

by using a breakstatement

for ( x = 101; x

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Skipping part of an iteration of the loop

Compute average of non-negative numbers

,

count = 0; sum = 0; // count and sum of non-negative numbers

for (i = 1; i

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How is character stored in memory

Normally between 0 and 127

The mapping used by our PCs is called ASCII

American Standard Code for Information Interchange

A few examples:

a is stored as 97 (and successive small-case letters by

consecutive integers, z is 122)

A is stored as 65 (Z is 90)

0 is stored as 48 (9 as 57)

Note that 0 is different from 0.

Lec-09 Dheeraj Sanghi, CSE Dept., IIT Kanpur

ESc101, 2011-12-Monsoon

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Character Representation

program

But you can assume that

All small case letters will be stored as consecutive numbers

The difference in z and a will always be 25

All capital case letters will be stored as consecutive numbers

All digits will be stored as consecutive numbers

The difference between 6 and 3 will always be 3

Lec-09 Dheeraj Sanghi, CSE Dept., IIT Kanpur

ESc101, 2011-12-Monsoon

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Printing a character

.

char gender;

gender = M;

printf(The gender is: %c\n, gender);

The above code will print the following:

The gender is: M

Lec-09 Dheeraj Sanghi, CSE Dept., IIT Kanpur

ESc101, 2011-12-Monsoon

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Reading a character

read.

scanf(%c, &c)

What if there are multiple characters to be read?

Lec-09 Dheeraj Sanghi, CSE Dept., IIT Kanpur

ESc101, 2011-12-Monsoon

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Inputting Multiple Characters: Version 1

char a, b, c;

rintf T e first character\n

scanf(%c, &a);

printf(Type second character\n);

scanf(%c, &b);

printf(Type third character\n);

scanf(%c, &c);

printf(%c\n%c\n%c\n, a, b, c);

Does not Work!

Enter is read as a

character.

Lec-09 Dheeraj Sanghi, CSE Dept., IIT Kanpur

ESc101, 2011-12-Monsoon

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Inputting Multiple Characters: Version 2

char a, b, c;

printf(Type three characters\n);

scanf(%c, &a);

scanf(%c, &b);scanf(%c, &c);

printf(%c\n%c\n%c\n, a, b, c);

You have to type all three characters together.

Lec-09 Dheeraj Sanghi, CSE Dept., IIT Kanpur

ESc101, 2011-12-Monsoon

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Inputting Multiple Characters: Version 3

char a, b, c;

rintf T e first character\n

scanf(%c, &a);

printf(Type second character\n);

scanf( %c, &b);

// Added a space before %c

printf(Type third character\n);

scanf( %c, &c);

// Added a space before %c

printf(%c\n%c\n%c\n, a, b, c);

Works!

We could fix the

newline problem.

Lec-09 Dheeraj Sanghi, CSE Dept., IIT Kanpur

ESc101, 2011-12-Monsoon

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Wishing you all a very

happy Rakhi and

Independence Day

Lec-09 Dheeraj Sanghi, CSE Dept., IIT Kanpur

ESc101, 2011-12-Monsoon

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