Problem Solving: Algorithm design
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Algorithm - a set of instructions independent of any programming language that calculates a function or solves a problem.
Express the solution to a simple problem as an algorithm using flowcharts, pseudo-code or structured English and the standard constructs:
Sequence
[edit | edit source]![](http://upload.wikimedia.org/wikipedia/commons/thumb/7/76/CPT-Sequence-diagram.svg/220px-CPT-Sequence-diagram.svg.png)
performing or operating each step consecutively in the order they arise
Console.writeline("This is line 1")
Console.writeline("This is line 2")
Console.writeline("This is line 3")
- include<stdio.h>
int main() {
// Read n int n; printf("Enter number n : "); scanf("%d", &n); // Declare sum to 0 // counter variable i to 1 int sum = 0; int i = 1; // loop to input n numbers // loop continues until i<=n for(i=1;i<=n;i++){ // read num int num ; printf("Enter number %d: ", i); scanf("%d", &num); // update sum to sum + num sum = sum + num; } // print sum printf("Sum of given numbers is %d", sum); return 0;
}
Selection
[edit | edit source]Selection is choosing a step
![](http://upload.wikimedia.org/wikipedia/commons/thumb/c/c5/If-Then-Else-diagram.svg/220px-If-Then-Else-diagram.svg.png)
If x > 0 then
Console.writeline("x is positive")
End If
If x = 0 then
Console.writeline("x equals 0")
End If
If x < 0 then
Console.writeline("x is negative")
End If
Repetition
[edit | edit source]A sequence of steps that loop until a requirement is met
![](http://upload.wikimedia.org/wikipedia/commons/thumb/9/92/Do-while-loop-diagram.svg/220px-Do-while-loop-diagram.svg.png)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/4/43/While-loop-diagram.svg/220px-While-loop-diagram.svg.png)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/6/61/CPT-For-loop-diagram-complex.svg/220px-CPT-For-loop-diagram-complex.svg.png)
x = 0
y = 5
Do
x = x + 1
Loop Until x = y