Hi this is Aamir we are going to learn how to program the Computer, that is, to tell it to do something for us.
This something could be calculating averages examination processing, payroll processing etc.
To do this we must speak with Computer. This speaking or communication must be done
Through a language Understood by the Computer and we are going to use BASIC as language for communication with Computer……
BASIC KEY WORDS
ABS DRAW LINE PAINT STEP
AND EDIT LIST PLAY STOP
ASC ELSE LLIST POS STR$
ATN END LOAD PRINT STRING$
AUTO EOF LOC PRINT# SWAP
BEEP FIELD LOCATE PSET SYSTEM
CHAIN FILES LOF PUT TAB
CHR$ FIX LOG RANDOMIZE TAN
CINT FNXXXXX LPRINT READ THEN
CIRCLE FOR LSET REM TIME$
CLOSE GET MERGE RENUM TIMER
CLS GUSUB MID$ RESTORE TO
COMMON GOTO MKD$ RETURN TROFF
CONT IF MKI$ RND USING
CSRLIN INPUT MOD RSET VAL
DATA INPUT# NAME RUN WEND
DATE$ INT NEW SAVE WHILE
DEF INSTR NEXT SCREEN WIDTH
DEFDBL KEY NOT SGN WRITE
DEFINT KEY$ OFF SIN WRITE#
DEFSNG KILL ON SOUND
DEFSTR LEET$ OPEN SPACE$
DELETE LEN OR SPC
DIM LET OUT SQR
Problem solving on computer
Developing the solution procedure.
Coding the solution procedure in computer understandable form.
Developing the solution procedure is one of the most important Task in problem solving.
All it involves is a liking for problem solving, a logical bent of mind, an eye for detail and a pen
And paper. Once the solution procedure is developed it can code in any computer language.
The step by step for solving the problem is also called as the logic of the problem or an
Algorithm For the problem.
Following points could be kept in mind while developing a solution procedure
a). Computer cannot solve a problem on their own.
We must give suitable instruction to the computer to solve the problem.
b). Computer do exactly what we instruct to them to do .
If by mistake we instruct the computer to calculate ,
Gross salary = Basic salary - HRA –DA,
It will perform the subtraction of HRA and DA, even though it is logically wrong.
Thus the responsibility of developing a correct logic for the solution of a problem lies with the user and not with the Computer.
c).Computers have no responsibility of their own.
Suppose we ask the computer to perform the following addition:
TOTAL = 1+2+3+4……. +10
A human being understand that the above statement means addition of all numbers upto 10,
But not the computer. It has to told in details as to what exactly it is suppose to do.
Therefore to perform the above addition it must be instructed as under:
TOTAL =1+2+3+4+5+6+7+8+9+10
Concept of Flow charting
A certain planning is essential before any problem solved.
This planning is necessary whether it is a problem in mathematics or an everyday problem like shopping.
Before going on a shopping trip one has to prepare list of items to be purchased, the order in which the various shops are to be visited, decided how much time and money to be spend etc.
Most of this planning is ofcourse often done sub-consciously.
But, when a problem is solved on computer it is essential to work out in detail all the decisions to be taken by the machine the action to be performed and the sequence in which these are to be performed.
This planning is aided by flow-charts
Flowchart is the most frequently used tool to develop a solution procedure. One should be skilled in drawing flow charts to be a successful programmer.
For easy understanding and uniformity in the flowcharts drawn people standard flowchart symbols are in use. Figure on the following page illustrates some of the most frequently used flowchart symbols.
TERMINAL – indicates the beginning or end of the
Solution procedure
PROCESSING – indicates arithmetic’s operaters.
INPUT/OUTPUT -indicates an operator of reading or writing.
DECISION BOX - indicates a decision point. A test is performed
(i.e. a condition is tested ) and the program
flow continues on each outgoing path
conditional to the answer to the test.
Annotation symbol- indicates a comment or a remark about thE Programe.
Example:
A man leaves work at the end of a day. If the time is 6.00 p.m. or earlier, he travels home by bus. If the time is later than 6.00 he has a meal in a cafe before travelling home, by bus.
Draw a flowchart of the men’s activities.
START
LEAVE WORK
LATER THAN
6.00?
HAVE A MEAL
TRAVEL HOME
BY BUS
NOTES:-
The flowchart is constructed from START terminal symbol by representing each activity as stated in the problem.
When two different activities, have a meal, not have a meal; are dependent upon the answer to a question, is time later than 6.00 p.m. ?, then the question is represented by a decision symbol, and the answer, by one of the two flow lines leaving the symbol.
Each symbol has been annotated in English describing the operation at that stage of the flowchart.
STOP
Problem solving with flowchart.
We want to perform the following operations on two numbers say * & 4.
8+4, 8-4, 8*4,
8/4, 8^4, 8\4,
And 8 mod 4
Since we want to solve this problem on a computer, we must first draw a flow chart.
STEP 1 START
STEP 2 A=8+4
STEP 3 B=8-4
STEP 4 C=8*4
STEP 5 D=8/4
STEP 6 E=8^4
STEP 7 F=8 MOD 4
STEP 8 G= 8\4
STEP 9 PRINT A,B,C,D,E,F,G
STEP 10 STOP
NOW A LITLE EXPLATION ABOUT THIS FLOWCHART---
STEP 1 INDICATES THAT AT THIS POINT THE LOGIC OR THE SOLUTION PROCEDURE FOR THE PROBLEM BEINGS. THIS IS ALWAYS INDICARED BY A MESSAGE ‘START’ WRITTEN IN AN OAL SHAPED BOX.
STEP 2 THROUGH 8 INDICATE THE DIFFERENT OPERATIONS THAT WE DESIRE TO PERFORM ON THE TWO NUMBERS 8 & 4 . THE RESULT OF THESE OPERATIONS SRE STORED IN VARIABLES. A,B,C,D,E,F,G. SINCE ALL THESE ARE ARITHMETIC OPERATIONS, THEY ARE ALWAYS ENCLOSED IN THE PROCESS SMBOL.
This something could be calculating averages examination processing, payroll processing etc.
To do this we must speak with Computer. This speaking or communication must be done
Through a language Understood by the Computer and we are going to use BASIC as language for communication with Computer……
BASIC KEY WORDS
ABS DRAW LINE PAINT STEP
AND EDIT LIST PLAY STOP
ASC ELSE LLIST POS STR$
ATN END LOAD PRINT STRING$
AUTO EOF LOC PRINT# SWAP
BEEP FIELD LOCATE PSET SYSTEM
CHAIN FILES LOF PUT TAB
CHR$ FIX LOG RANDOMIZE TAN
CINT FNXXXXX LPRINT READ THEN
CIRCLE FOR LSET REM TIME$
CLOSE GET MERGE RENUM TIMER
CLS GUSUB MID$ RESTORE TO
COMMON GOTO MKD$ RETURN TROFF
CONT IF MKI$ RND USING
CSRLIN INPUT MOD RSET VAL
DATA INPUT# NAME RUN WEND
DATE$ INT NEW SAVE WHILE
DEF INSTR NEXT SCREEN WIDTH
DEFDBL KEY NOT SGN WRITE
DEFINT KEY$ OFF SIN WRITE#
DEFSNG KILL ON SOUND
DEFSTR LEET$ OPEN SPACE$
DELETE LEN OR SPC
DIM LET OUT SQR
Problem solving on computer
Developing the solution procedure.
Coding the solution procedure in computer understandable form.
Developing the solution procedure is one of the most important Task in problem solving.
All it involves is a liking for problem solving, a logical bent of mind, an eye for detail and a pen
And paper. Once the solution procedure is developed it can code in any computer language.
The step by step for solving the problem is also called as the logic of the problem or an
Algorithm For the problem.
Following points could be kept in mind while developing a solution procedure
a). Computer cannot solve a problem on their own.
We must give suitable instruction to the computer to solve the problem.
b). Computer do exactly what we instruct to them to do .
If by mistake we instruct the computer to calculate ,
Gross salary = Basic salary - HRA –DA,
It will perform the subtraction of HRA and DA, even though it is logically wrong.
Thus the responsibility of developing a correct logic for the solution of a problem lies with the user and not with the Computer.
c).Computers have no responsibility of their own.
Suppose we ask the computer to perform the following addition:
TOTAL = 1+2+3+4……. +10
A human being understand that the above statement means addition of all numbers upto 10,
But not the computer. It has to told in details as to what exactly it is suppose to do.
Therefore to perform the above addition it must be instructed as under:
TOTAL =1+2+3+4+5+6+7+8+9+10
Concept of Flow charting
A certain planning is essential before any problem solved.
This planning is necessary whether it is a problem in mathematics or an everyday problem like shopping.
Before going on a shopping trip one has to prepare list of items to be purchased, the order in which the various shops are to be visited, decided how much time and money to be spend etc.
Most of this planning is ofcourse often done sub-consciously.
But, when a problem is solved on computer it is essential to work out in detail all the decisions to be taken by the machine the action to be performed and the sequence in which these are to be performed.
This planning is aided by flow-charts
Flowchart is the most frequently used tool to develop a solution procedure. One should be skilled in drawing flow charts to be a successful programmer.
For easy understanding and uniformity in the flowcharts drawn people standard flowchart symbols are in use. Figure on the following page illustrates some of the most frequently used flowchart symbols.
TERMINAL – indicates the beginning or end of the
Solution procedure
PROCESSING – indicates arithmetic’s operaters.
INPUT/OUTPUT -indicates an operator of reading or writing.
DECISION BOX - indicates a decision point. A test is performed
(i.e. a condition is tested ) and the program
flow continues on each outgoing path
conditional to the answer to the test.
Annotation symbol- indicates a comment or a remark about thE Programe.
Example:
A man leaves work at the end of a day. If the time is 6.00 p.m. or earlier, he travels home by bus. If the time is later than 6.00 he has a meal in a cafe before travelling home, by bus.
Draw a flowchart of the men’s activities.
START
LEAVE WORK
LATER THAN
6.00?
HAVE A MEAL
TRAVEL HOME
BY BUS
NOTES:-
The flowchart is constructed from START terminal symbol by representing each activity as stated in the problem.
When two different activities, have a meal, not have a meal; are dependent upon the answer to a question, is time later than 6.00 p.m. ?, then the question is represented by a decision symbol, and the answer, by one of the two flow lines leaving the symbol.
Each symbol has been annotated in English describing the operation at that stage of the flowchart.
STOP
Problem solving with flowchart.
We want to perform the following operations on two numbers say * & 4.
8+4, 8-4, 8*4,
8/4, 8^4, 8\4,
And 8 mod 4
Since we want to solve this problem on a computer, we must first draw a flow chart.
STEP 1 START
STEP 2 A=8+4
STEP 3 B=8-4
STEP 4 C=8*4
STEP 5 D=8/4
STEP 6 E=8^4
STEP 7 F=8 MOD 4
STEP 8 G= 8\4
STEP 9 PRINT A,B,C,D,E,F,G
STEP 10 STOP
NOW A LITLE EXPLATION ABOUT THIS FLOWCHART---
STEP 1 INDICATES THAT AT THIS POINT THE LOGIC OR THE SOLUTION PROCEDURE FOR THE PROBLEM BEINGS. THIS IS ALWAYS INDICARED BY A MESSAGE ‘START’ WRITTEN IN AN OAL SHAPED BOX.
STEP 2 THROUGH 8 INDICATE THE DIFFERENT OPERATIONS THAT WE DESIRE TO PERFORM ON THE TWO NUMBERS 8 & 4 . THE RESULT OF THESE OPERATIONS SRE STORED IN VARIABLES. A,B,C,D,E,F,G. SINCE ALL THESE ARE ARITHMETIC OPERATIONS, THEY ARE ALWAYS ENCLOSED IN THE PROCESS SMBOL.
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