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i<=5
i:=i+1;
i=1;
Y
while i<=5 do
i:=1;
writeln(i);
i:=i+1;
begin
end;
i=1 output 1
i=2 output 2
i=3 output 3
i=4 output 4
i=5 output 5
i=6 ?writeln(i);
Ex.1 Use “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!
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 … segmentwhile…do … segment
Ex.1 Use “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.
n>=0
Y
write(‘Input an integer’);readln(n);
writeln(‘Square of ’,n,’ is ’,sqr(n));
write(‘Input an integer’);readln(n);
N
writeln(‘Bye!’);
input n>=0
n=9
n=4
n=7
n=-1
Y
Y
Y
N
Ex.1Ex.1
program ex1;
var n:integer;
beginwriteln(‘Welcome!’);write(‘Input an integer: ’);readln(n);while n>=0 dobegin
writeln(‘Square of ’,n,‘ is ’,sqr(n));write(‘Input an integer: ’);readln(n);
end;writeln(‘Bye!’);
end.
writeln(i);
i:=1;
i:=i+1;
repeat
until i>5;i>5
i:=1;
N
i:=i+1;
i>5
writeln(i);i=2 N
i=3 N
i=4 N
i=5 N
i=6 ?
writeln(i);
i:=1;
i:=i+1;
repeat
until i>5;i>5
i:=1;
Y
i:=i+1;
end.
writeln(i);
i>5
i=2 N
i=3 N
i=4 N
i=5 N
i=6 Y
Condition
Process 2
Process 1
Process 3
Y
N
Condition
Process 2
Process 1
N
Y
Process 3
Compare Compare while … do …while … do … and and repeat … until ...repeat … until ...
Condition
Condition
Process 2
Process 2
Ex.2 Use “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!
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 … segmentrepeat …until … segment
Ex.2 Use “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.
n<0
Y
write(‘Input an integer’);readln(n);
writeln(‘Square of ’,n,’ is ’,sqr(n));
write(‘Input an integer’);readln(n);
N
writeln(‘Bye!’);
input n<0
n=9
n=4
n=7
n=-1
N
N
N
Y
Ex.2Ex.2