5.7: Case Study- Display a Rectangle
- Page ID
- 126727
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Example
Write a program that displays a rectangle as following:
****************************
* *
* *
* *
* *
****************************
We first write a program as following with a nested loop statement:
There are two statements inside of outer loop. One of them is a for loop statement:
for(int j=0;j<lengthl;j++){
cout<<"* ";
}
If a user enter 10 for the length and 7 for the width, then above loop statement will display 10 asterisks in a row. the second statement in the outer loop is
cout<<endl;
This statement will move the cursor to the beginning of the next line, so the next print will start at the beginning of next line.
The outer loop will execute those two statement 7 times, Thus the program will display 7 rows of the asterisks with 10 asterisks in each row:
However, this is not what we want. We only want the asterisks around the rectangle, but not inside of the rectangle. In other words, we only want the first row (when i=0) and the last row (when i=width-1) to be full rows of asterisks, from the second row (i=1) to the second to the last row (i=width-2), we only want the first column (j=0) and the last column (j=length-1) to be an asterisk and the rest of those column (from j=2 to j=length-2) to white spaces.
Now, we revise above program by adding an if-else statement shown as following:
The output of this revised program is shown as following:
If you would like to check if you actually understand above program, please try to write a program that displays a rectangle as following:
