Conditional Compilation In C: #ifdef #else #endif

In this video tutorial lets learn about preprocessor command or directives like #ifdef, #else and #endif. These directives are used for conditional compilation.

When To Use #ifdef
1. When we want the compiler to skip certain part of the source code: For this we could even use multi-line comment, but if we already had multi-line comments in the code, we can’t enclose the source code and multi-line comments with another multi-line comment. Nesting of multi-line comments are not allowed in C programming language. So instead of commenting the code we could make use of #ifdef directive.

2. To write portable code: For example, we could write code both for iOS and non-iOS devices. Using #ifdef we could check the device OS and based on that deliver specific set of codes. For this we can use #ifdef

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[idellius]

Thank you for this video. It's exactly what I was looking for.

[srujanprabhu]

I understood very clearly brother, Thank you so much

[hnbaraiya]

i think you start a new channel in which you explain topics of c.

[rishikeshpandey]

Nice ....what
If i want to remove all comments of c source code or program
Can u help me ..plz