unit3 - Ranking of 60 students in a class int main...

/* Ranking of 60 students in a class */
int main() {
/*declaring 60 varialbes */
int score0, score1,score2,……,score59;
/* Reading scores for sixty times */
printf(“Enter the score : “);
scanf(“%d”, &score0);
…. …. …. ….
printf(“Enter the score : “);
scanf(“%d”, &score59);
/* comparing & swapping for 1770 times
* to arrange in descending order */
swap( score0, score1);
swap( score1, score2);
swap( score2, score3);
…. …. …. ….
swap( score0,score1);
swap( score1,score2);
swap( score0,score1);
/*printing 60 scores after sorting */
printf(“%4d”, score0);
printf(“%4d”, score1);
… … … …
}
void swap ( int a, int b) {
int temp;
if( a < b) {
temp = a ; a = b ; b = temp;
}
}
score0
score1
score2
score3
.
.
score59
scores[0]
scores[1]
scores[2]
scores[3]
.
.
scores[59]
#include<stdio.h>
int main() {
int scores[60] , i , j, temp;
for(i = 0; i < 60 ;i++) {
printf("Enter the score : ");
scanf("%d", &scores[i]);
}
for(i=0;i<(60-1);i++)
for( j=0; j <(60 -(i+1)); j++)
if(scores[ j ] < scores[ j +1]) {
temp = scores[ j ];
scores[ j ] = scores[ j +1];
scores[ j + 1] = temp;
}
for( i = 0; i < 60; i ++) printf("%4d", scores[i]);
}
Sixty variables are replaced by one Array
Sixty input
statements are
called by one loop
statement
1770 comparing
statements are
included in one
loop statement
Array & its Advantage

scores[0]
scores[1] scores[2]
scores[3] scores[4]
scores Array
. . .
start here
4022 4023 4024 4025 4026
4027
4028 4029 4030 4031
( memory
addresses)
Mean can be calculated only after reading all scores. Each deviation is difference of individual
score and mean. To calculate deviations of all scores, scores must be stored in an ARRAY.
Initialization of Array
Declaration of Array
Processing on Array
Input to an element
Accessing
an element

Scalar Variables :

A variable represents a data item and it can be used to store a single atomic value at a
time. These are also called scalar variables.

Integer takes 2 bytes memory as a single unit to store its value. i.e.,the value of a scalar
variable cannot be subdivided into a more simpler data items.

The address of first byte is the address of a variable .
Vector Variables (arrays) :

In contrast, an array is multivariable (an aggregate data type), which is also referred to a
data structure. It represents a collection of related data items of same type.

An individual data item of an array is called as ‘element’. Every element is accessed by
index or subscript enclosed in square brackets followed after the array name.

All its elements are stored in consecutive memory locations, referred under a common
array name.
Ex : int marks[10] ; /* declaration of array */

‘0’ is first number in computer environment. The first element of array marks is marks[0]
and last element is marks[9]. (the address of first element is the address of the array)

An array is a derived data type. It has additional operations for retrieve and update the
individual values.

The lowest address corresponds to the first element and the highest address to the last
element.