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, 7785👍, 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, 7786👍, 0💬

What does static variable mean
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Storage Classes
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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, 6875👍, 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, 6836👍, 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, 6775👍, 0💬

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