Macro vs. Function

Q

Advantages of a macro over a function?

✍: FYIcenter

A

Macro gets to see the Compilation environment, so it can expand __DATE__ __TIME__ __FILE__ #defines. It is expanded by the preprocessor.

For example, you can't do this without macros.

#define PRINT(EXPR) printf( #EXPR "=%d\n", EXPR)
PRINT( 5+6*7 ) // expands into printf("5+6*7=%d",
5+6*7);

You can define your mini language with macros:

#define strequal(A,B) (!strcmp(A,B))

Macros are a necessary evils of life. The purists don't like them, but without it no real work gets done.

2007-02-26, 7933👍, 0💬

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Macro vs. Function
Advantages of a macro over a function? Macro gets to see the Compilation environment, so it can expand __DATE__ __TIME__ __FILE__ #defines. It is expanded by the preprocessor. For example, you can't do this without macros. #define PRINT(EXPR) printf( #EXPR "=%d\n", EXPR) PRINT( 5+6*7 ) // expands in... 2007-02-26, 7934👍, 0💬

What does static variable mean
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Storage Classes
What are the different storage classes in C? C has three types of storage: automatic, static and allocated. Variable having block scope and without static specifier have automatic storage duration. Variables with block scope, and with static specifier have static scope. Global variables (i.e, file s... 2007-02-26, 7440👍, 0💬

Strings vs. Character Arrays
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Conditional Statements
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Conditional Statements
What will happen in these three cases? if (a=0) { //somecode } if (a==0) { //do something } if (a===0) { //do something } 2007-02-26, 7011👍, 0💬

Multi-dimension Arrays
Write down the equivalent pointer expression for referring the same element a[i][j][k][l]? a[i] == *(a+i) a[i][j] == *(*(a+i)+j) a[i][j][k] == *(*(*(a+i)+j)+k) a[i][j][k][l] == *(*(*(*(a+i)+j)+k)+l) 2007-02-26, 6939👍, 0💬

Variable Types
What are the types of variables x, y, y and u defined in the following code? #define Atype int* typedef int *p; p x, z; Atype y, u; Answer: x and z are pointers to int. y is a pointer to int but u is just an integer variable 2007-02-26, 6895👍, 0💬

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