puzzled by sizeof(string)

void setup()
{
   serial.begin(9600);

}

void loop()
{
 char cmcs[15]="8613800571500";
 get(cmcs);
 delay(2000);
}

void get(char cmcsd[]){
serial.println(sizeof(cmcsd));
}


why result 2,but not 15

jerry,

if trying find out how many characters there in string (from start nul terminator), should use strlen

code: [select]

void get(char cmcsd[]){
serial.println(strlen(cmcsd));
}
sizeof not function.  it's calculated compiler when program compiled, , of course compiler can't know how many characters going put string.

sizeof gives number of bytes taken thing inside parentheses.  you passed character pointer, uses 2 bytes of memory.

if have array of fixed size in routine, sizeof can tell how many bytes whole array takes up, when use sizeof within routine.  this 1 of subtle differences between array , pointer.  for example

code: [select]

char my_string[25];
serial.println(sizeof(my_string));will print out 25.

-mike

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