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Section 2.5 Outputting Variables
You can output the value of a variable using the same commands we used to output simple values. The program below creates two integer variables named hour and minute, and a character variable named colon. It assigns appropriate values to each of the variables and then uses a series of output statements to generate the following:
The current time is 11:59
Run the code. After observing the output, try modifying the assignment statements to make a different time!
Listing 2.5.1. This program outputs the current time, according to the values you provide for hour and minute.When we talk about βoutputting a variable,β we mean outputting the
value of the variable. To output the
name of a variable, you have to put it in quotes. For example:
cout << "hour";
The output of this statement is as follows.
As we have seen before, you can include more than one value in a single output statement, which can make the previous program more concise:
Listing 2.5.2. This program does the same thing as the previous, but the print statements have been condensed to one line. This is better style.On one line, this program outputs a string, two integers, a character, and the special value
endl
. Very impressive!
Checkpoint 2.5.1 .
What prints when the following code is run?
int main() {
char a;
char b;
a = 'z';
b = '8';
cout << "a";
}
The string, not the variable, a will be printed.
b will not be printed.
The cout statement prints a, not the value of the variable a.
z is the value of a and 8 will not be printed
Nothing! There will be a compile error!
There is no type mismatch, so there will not be a compile error.
Checkpoint 2.5.2 .
int main() {
char a;
char b;
a = 'z';
b = '8';
cout << b;
}
The string a will not be printed.
The string b will not be printed.
z is the value of a and 3 will not be printed.
8 is the value of b will be printed!
Nothing! There will be a compile error!
There is no type mismatch, so there will not be a compile error.
Checkpoint 2.5.3 .
int main() {
int x;
char y;
x = '3';
y = 'e';
cout << 'y';
}
Take a look at the code again.
Take a look at the code again.
Take a look at the code again.
Take a look at the code again.
Nothing! There will be a compile error!
There is a type mismatch, so there will be a compile error!
Checkpoint 2.5.4 .
Match the variable initialization to its correct type. Do so by dragging items on the left to the matching box on the right.
Try again!
int
string
char
Checkpoint 2.5.5 .
Construct a main function that assigns βHelloβ to the variable h, then prints out hβs value.
int main() {
---
string h;
---
char h; #paired
---
h = "Hello";
---
h = Hello; #paired
---
cout << h;
---
cout << "Hello"; #paired
---
cout << "h";
---
}
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