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FLOWCHART : IF
FLOWCHART :
NESTED IF
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FLOWCHART : IF… ELSE
FLOWCHART : SWITCH
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FLOWCHART : WHILE LOOP
FLOWCHART : DO..WHILE LOOP
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FOR LOOP
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Sunday 14 October 2012
FLOWCHART-IZZHAM AND SYAMIN
FLOWCHART : IF
FLOWCHART : IF… ELSE
FLOWCHART : WHILE LOOP
FLOWCHART : DO..WHILE LOOP
Arrays-IZZHAM AND SYAMIN
Arrays
Array is data structure used to share multiple data elements under a single name declaration.
It's important that every single element of data, we wish to assign to array, belongs to the same data type.
Arrayâ's elements are easily accessed -
we use index; a number that must be nonnegative integer (constant, variable, integer expression).
Element's index is a number between 0 and the number of elements minus one, including. In short: Index ( [0, NrOfElements-1].
Declaration of an array:
data_type array_name[index];
Array's definition in C:
int x[20] - array consisted of 20 integer numbers
char symbols[2] - array consisted of 2 characters
float sequence[MAX] - MAX is constant
Assigning element's values definition:
int array[ ] = {1, 2, 3};
array[0] = 1
array[1] = 2
array[2] = 3
int array [4] = {1, 2};
array[0] = 1
array[1] = 2
array[2] = 0
array[3] = 0
Accessing array's elements:
x[0] - first element of an array
sequence[i] -i. element of an array, 0 <= i <= NrOfElements-1
sequence[MAX-1] last element of an array
Common Wrong access to array's elements:
int array[10] = {0};
int x = sequence[10];
float a = 1.;
int x = array[a];
int a = 1, b = 0, c = 1;
int x = array[(a && b) - c];
Example:
Write your own program that asks user to input sequence of numbers, afterwards it calculates arithmetic middle of the given sequence.
Program also prints numbers smaller than arithmetic middle, and afterwards prints numbers bigger than arithmetic middle.
#include <stdio.h>
#define DIMENSION 10
int main(void) {
int i;
float sum = 0., arit_midd = 0., sequence[DIMENSION]={0};
for (i = 0; i < DIMENSION; i++) {
printf("Input number: ");
scanf("%f",&sequence[i]);
sum += sequence[i];
}
arit_midd = sum / DIMENSION;
printf("Arithmetic middle of the sequence is %6.2f.\n", arit_midd);
for (i = 0; i < DIMENSION; i++) {
if (sequence[i] < arit_midd) {
printf("%6.2f is smaller than arithmetic middle.\n", sequence[i]);
}
}
for (i = 0; i < DIMENSION; i++) {
if (sequence[i] > arit_midd) {
printf("%6.2f is bigger than arithmetic middle.\n", sequence[i]);
}
}
// What happens if the number is equal to arithmetic middle?
}
Example:
Write your own program that asks for input of sequence of numbers. After the program reads given numbers,
it divides every number with the biggest sequence element and shows them in a way relative to the biggest element.
#include <stdio.h>
#define DIMENSION 10
int main(void) {
int i;
float max, array[DIMENSION];
for (i = 0; i < DIMENSION; i++) {
printf("array[%d] = ", i);
scanf("%f",& array[i]);
if (i == 0) {
max = array[i];
}
if (max < array[i]) {
max = array[i];
}
}
printf("Biggest element in array is %f.\n\n", max);
for (i = 0; i < DIMENSION; i++) {
array[i] /= max;
printf("array[%d] = %f\n", i, array[i]);
}
}
Example:
Compose your own program that reads given natural numbers that belong in [10, 99] interval and counts how many times each number showed up.
Program stops reading numbers when element that doesn’t belong to interval is given. Af
afterwards, program prints each number from the interval that has showed at least once, and number of times it has really been given.
#include <stdio.h>
#define LL 10 /* lower limit of the interval */
#define UL 99 /* upper limit of the interval */
int main(void) {
int number, i;
int counter[UL – LL + 1] = { 0 };
do {
printf("\nInput number from interval [%d, %d]: ", LL, UL);
scanf("%d", &number);
if (number >= LL && number <= UL) {
counter[number - LL]++;
}
} while (number >= LL && number <= UL);
for (i = DG; i <= UL; i++) {
if (counter[i - LL] > 0) {
printf("\nNumber %d showed up %d times", i, counter [i - LL]);
}
}
}
Multi dimensional Arrays:
Often there is a need to store and manipulate two
dimensional data structure such as matrices & tables. Here the array has
two subscripts. One subscript denotes the row & the other the column. The declaration of two dimension arrays is as follows:
data_type array_name[row_size][column_size];
int m[10][20]
Here m is declared as a matrix having 10 rows( numbered from 0 to 9) and 20 columns(numbered 0 through 19). The first element of the matrix is m[0][0] and the last row last column is m[9][19]
Elements of multi dimension arrays:
A 2 dimensional array marks [4][3] is shown below figure.
The first element is given by marks [0][0] contains 35.5 & second element
is marks [0][1] and contains 40.5 and so on. |
marks
[0][0]
35.5 |
marks
[0][1]
40.5 |
marks
[0][2]
45.5 |
|
marks
[1][0]
50.5 |
marks
[1][1]
55.5 |
marks
[1][2]
60.5 |
|
marks
[2][0]
|
marks
[2][1]
|
marks
[2][2]
|
|
marks
[3][0]
|
marks
[3][1]
|
marks
[3][2]
|
Initialization of multidimensional
arrays:
Like the one dimension arrays, 2 dimension arrays may be
initialized by following their declaration with a list of initial values
enclosed in braces Example:
int table[2][3]={0,0,0,1,1,1};
Initializes the elements of first row to zero and second row to 1. The initialization is done row by row. The above statement can be equivalently written as
int table[2][3]={{0,0,0},{1,1,1}}
By surrounding the elements of each row by braces.
C allows arrays of three or more dimensions. The compiler determines the maximum number of dimension. The general form of a multidimensional array declaration is:
date_type array_name[s1][s2][s3]…..[sn];
Where s is the size of the ith dimension. Some examples are:
int survey[3][5][12];
float table[5][4][5][3];
Survey is a 3 dimensional array declared to contain 180 integer elements. Similarly table is a four dimensional array containing 300 elements of floating point type.
/*
example program to add two matrices & store the results in the 3rd matrix
*/
#include< stdio.h >
#include< stdio.h >
void
main()
{
int a[10][10],b[10][10],c[10][10],i,j,m,n,p,q;
{
int a[10][10],b[10][10],c[10][10],i,j,m,n,p,q;
printf(“enter
the order of the matrix\n”);
scanf(“%d%d”,&p,&q);
scanf(“%d%d”,&p,&q);
if(m==p && n==q)
{
printf(“matrix can be added\nn”);
printf(“enter the elements of the matrix a”);
for(i=0;i < m;i++)
for(j=0;j < n;j++)
scanf(“%d”,&a[i][j]);
printf(“enter the elements of the
matrix b”);
for(i=0;i < p;i++)
for(j=0;j < q;j++)
scanf(“%d”,&b[i][j]);
for(j=0;j < q;j++)
scanf(“%d”,&b[i][j]);
printf(“the sum of the
matrix a and b is”);
for(i=0;i < m;i++)
for(j=0;j < n;j++)
c[i][j]=a[i][j]+b[i][j];
for(i=0;i < m;i++)
for(j=0;j < n;j++)
c[i][j]=a[i][j]+b[i][j];
for(i=0;i < m;i++)
{
for(j=0;j < n;j++)
printf(“%dt”,&a[i][j]);
printf(“n”);
}
}
}
Basic Structure of C program-IZZHAM AND SYAMIN
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All C programs consist of the following elements:
Explanations
preprocessor Refer to
next page
main() Every program must have a main() function and it
is a first function that will be called.
The
main() function is the one to which control is passes when the program is
executed.
{ } These
are known as braces or curly brackets.
The statements of the functions
are enclosed in these curly brackets. The opening curly brackets indicates that
a block of statements is about to begin. the closing curly brackets terminates
the block of the statements.
Example
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Explanation
//A first ....... It is a comments.
#include <stdio.h> It is one of the preprocessor directives.
Line begins with # are processed by the preprocessor before the program is
compiled. This specific line tells the
preprocessor to include in the program the contents of the standard input/output stream
header file
printf Also called console output, instruct the computer to print on the screen the
string of characters contained between the quotation marks.
\ This is called escape character.Some common escape sequences ie \n.
\n The escape sequence means newline.
return 0 This statements terminates
the function containing it and return the specified value to that function
caller. In this example, it will terminate main and return 0 to its caller.
Console Output (printf)
printf is an object of the stdio
class and is said to be “tied to” or connected to the standard output device,
normally the display screen.
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Header File
Standard libraries (and most C libraries) typically come with what
are called “Header files”. These files provide information to the C compiler
about the inputs and results produce by each function in the libraries. Header files usually accessed by the #include
directive.
Preprocessor Directives
Preprocessing occurs before a program is compiled. Some possible
actions are : inclusion of other files in the file being compiled, definition
of symbolic constants and macros, conditional compilation of program code and
conditional execution of preprocessor directives. Preprocessing refer to the first step in
translating. All preprocesssor
directives begin with #. Preprocessor
directives are not C statements, so they
do not end in (;). It is processed fully
before compilation begins. You can
utilize three major capabilities of the preprocessor to make your programs
modular, more readable and easier to
customize:
1. #include
This
directive is to insert the contents of a file into your program. With this, you
can place common declarations in one location and use them in all source file
through file inclusion. The result is a
reduced risk of mismatches between declarations of variables and functions in
separate program modules. If the file is enclosed in angle brackets ( < and
> ) - used for standard header files.
Examples:
#include
<stdio.h>
2. #define
This
directive define macros that enable you to replace one string with
another. You can use it to give meaningful
names to numeric constants, thus improving constants, thus improving the readability of your source
files.
Examples:
#define
PI 3.149
3.
With directives such as
#if, #ifdef, #else and #endif, you can compile only selected portion of your
program. You can use this feature to
write source files with code for two nor more systems, but compile only those parts that apply to
the computer system on which you compile the program. With this strategy , you can maintain multiple versions of a
program using a single set of source files.
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Example
Escape Sequence
An escape sequences always begins with the backslash \
and is followed by one or more special characters.
Escape Sequence
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Description
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\n
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Newline
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\t
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Horizontal tab
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\a
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Alert. Sound
the system bell
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\\
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Backslash.
Used to print backslash character.
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\”
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Double quote.
Used to print double quote character.
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Example
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Commenting of C
programs
C programs can include comments that provide information to a person
reading the program. Comments in C are preceded by the two characters / and * and are followed by the same
characters * and / in reversed order. A
most common feature of most programs written by professional programmers is
that there is a program heading as shown below:
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