Learn to Program with C_ Learn to Program using the Popular C Programming Language ( PDFDrive )

Chapter 5 ■ Programs with Repetition Logic
When a for statement is encountered, it is executed as follows:
1. <expr1> is evaluated.
2. <expr2> is evaluated. If it is false, execution continues with the
statement, if any, after <statement>. If it is true, <statement> is
executed, followed by <expr3>, and this step (2) is repeated.
This can be expressed more concisely as follows:
<expr1>;
while (<expr2>) {
<statement>;
<expr3>;
}
Consider the following:
for (h = 1; h <= 5; h++)
printf("I must not sleep in class\n");
• h = 1 is <expr1>
• h <= 5 is <expr2>
• h++ is <expr3>
• <statement> is printf(...);
This code is executed as follows:
1. h is set to 1
2. The test h <= 5 is performed. It is true, so the body of the loop is executed
(one line is printed). The reinitialization step h++ is then performed, so h
is now 2.
3. The test h <= 5 is again performed. It is true, so the body of the loop is
executed (a second line is printed); h++ is performed, so h is now 3.
4. The test h <= 5 is again performed. It is true, so the body of the loop is
executed (a third line is printed); h++ is performed, so h is now 4.
5. The test h <= 5 is again performed. It is true, so the body of the loop is
executed (a fourth line is printed); h++ is performed, so h is now 5.
6. The test h <= 5 is again performed. It is true, so the body of the loop is
executed (a fifth line is printed); h++ is performed, so h is now 6.
7. The test h <= 5 is again performed. It is now false, so execution of the
for loop ends and the program continues with the statement, if any, after
printf(...).
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