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Looping. while … do …. Repeated Loop. Process 1. Condition. Y. Process 2. Process 1. N. Condition. Process 3. while … do. Process 1. N. Condition. Y. Process 2. Process 3. i=6. i=5. i=4. i=3. i=1. i=2. ?. output 3. output 2. output 5. output 1. output 4. i=1;. i:=1;.
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Looping while … do …
Repeated Loop Process 1 Condition Y Process 2
Process 1 N Condition Process 3
while … do ... Process 1 N Condition Y Process 2 Process 3
i=6 i=5 i=4 i=3 i=1 i=2 ? output 3 output 2 output 5 output 1 output 4 i=1; i:=1; i<=5 while i<=5 do Y begin writeln(i); writeln(i); i:=i+1; i:=i+1; end;
i=1; i<=5 N end.
i=1; i<=5 N Y writeln(i); end. i:=i+1;
Ex.1Use “while…do” to write a program to accept any integer and output its square value until the user input a negative number. The output should be as follow. The value after “:” is inputted by user. Welcome! Input an integer: 9 Square of 9 is 81 Input an integer:4 Square of 4 is 16 Input an integer:7 Square of 7 is 49 Input an integer: -1 Bye!
Ex.1Use “while…do” to write a program to accept any integer and output its square value until the user input a negative number. The output should be as follow. The value after “:” is inputted by user. Welcome! Input an integer: 9 Square of 9 is 81 Input an integer:4 Square of 4 is 16 Input an integer:7 Square of 7 is 49 Input an integer: -1 Bye! while…do … segment
input n>=0 n=-1 n=7 n=4 n=9 Ex.1 write(‘Input an integer’); readln(n); n>=0 N Y Y Y Y N writeln(‘Square of ’, n,’ is ’,sqr(n)); writeln(‘Bye!’); write(‘Input an integer’); readln(n);
program ex1; var n:integer; begin writeln(‘Welcome!’); write(‘Input an integer: ’); readln(n); while n>=0 do begin writeln(‘Square of ’,n,‘ is ’,sqr(n)); write(‘Input an integer: ’); readln(n); end; writeln(‘Bye!’); end.
Looping repeat … until …
Repeated Loop Process 1 Process 2 Condition N
Process 1 Process 2 Condition Y Process 3
repeat … until ... Process 1 Process 2 Condition N Y Process 3
i=2 N i=3 N i=4 N i=5 N i=6 ? i:=1; i:=1; i>5 repeat writeln(i); writeln(i); i:=i+1; i:=i+1; i>5 N until i>5;
i=2 N i=3 N i=4 N i=5 N i=6 Y i:=1; i:=1; i>5 repeat writeln(i); writeln(i); i:=i+1; i:=i+1; i>5 until i>5; Y end.
i:=1; i:=1; repeat writeln(i); writeln(i); i:=i+1; i:=i+1; i>5 N until i>5; Y end.
Compare while … do … and repeat … until ... Process 1 Process 1 Process 2 Process 2 N Condition Condition Y Condition Condition N Process 2 Process 2 Process 3 Y Process 3
Ex.2Use “repeat …until” to write a program to accept any integer and output its square value until the user inputs a negative number. The output should be as follows. The value after “:” is inputted by user. Welcome! Input an integer: 9 Square of 9 is 81 Input an integer:4 Square of 4 is 16 Input an integer:7 Square of 7 is 49 Input an integer: -1 Bye!
Ex.2Use “repeat …until” to write a program to accept any integer and output its square value until the user inputs a negative number. The output should be as follows. The value after “:” is inputted by user. Welcome! Input an integer: 9 Square of 9 is 81 Input an integer:4 Square of 4 is 16 Input an integer:7 Square of 7 is 49 Input an integer: -1 Bye! repeat …until … segment
input n<0 n=-1 n=7 n=4 n=9 Ex.2 write(‘Input an integer’); readln(n); writeln(‘Square of ’, n,’ is ’,sqr(n)); N N write(‘Input an integer’); readln(n); N Y n<0 N Y writeln(‘Bye!’);
program ex2; var n:integer; begin writeln(‘Welcome!’); write(‘Input an integer: ’); readln(n); repeat writeln(‘Square of ’,n,‘ is ’,sqr(n)); write(‘Input an integer: ’); readln(n); until (n<0); writeln(‘Bye!’); end.