Overview#if/#endif statements are commonly used to generate different compilation results based on the same source code, the most common of which is the debug and release versions. However, these tools are not very friendly in practical applications
4.2 Item Selection Statements"Teacher, did I pass the level four exam?" ”If the teacher is asked this question, how will he answer? Yes, he will choose different answers according to different conditions:If the test result is greater than or equal
4.2 Item Selection Statements"Teacher, did I pass the level four exam?" ”If the teacher is asked this question, how will he answer? Yes, he will choose different answers according to different conditions:If the test result is greater than or equal
If statement
The IF statement can be used to form a branch structure that is judged according to the conditions given to determine which branch segment to execute.
There are three basic forms of if statements in C language
The first form of:
Simplified condition expression 1. Decompose Conditional decomposition condition expression
You have a complex conditional statement.Separate independent functions from the if, then, and else sections..
Among programs, complex conditional logic is
"Conditional judgment"1. Judging by file type-B file to determine if the file exists and is a block device file (is a block device file is true)-c file to determine if the file exists and is a character device file (the character device file is true)
3 forms of an IF statement
1 an if (expression) statement.
For example:
if (x>y) cout
The execution of this if statement is shown in the following figure.
2 if (expression) statement 1 Else Statement 2
For example:
if (x>y)
Program flow control Statements in Java include conditional structure, loop structure, and jump statements4.1-Piece structureThe conditional structure includes the sequential structure and the selection structure. The sequential structure does not
Conditional compilation and c ++ Conditional compilation
1. ifdef
#ifdef XXXXX......#endifIf XXXXX is defined, compile the above Code.
2. ifndef
#ifndef XXXXX......#endifIf XXXXX is not defined, compile the above Code.
3. if
#if
//#if Conditional Compilation//language packs typically used for each version of the product#include #include//#都是预处理指令, the conditional expression must be in pre-processing//So the conditional expression must be a macro expression//Two-branch
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.