SOLVED:string length after strtok

Using Arduino Programming Questions
1 
void setup() {
  // put your setup code here, to run once:
Serial.begin(115200);

char original[50]="+CIPSNTPTIME:Fri Jun 01 22:55:56 2018";
char temp[50]={0};
byte b=0;

strcpy(temp,original);
Serial.print("temp length=");
Serial.println(strlen(temp));

strtok(temp,":");
Serial.print("temp length after strtok=");
Serial.println(strlen(temp));

for(byte i=0,b=strlen(temp);b<strlen(original);i++,b++){
  
  temp[i]=original[b];
  Serial.print("i=");
  Serial.print(i);
  Serial.print('\t');
  Serial.print("b=");
  Serial.print(b);
  Serial.print('\t');
  
  Serial.write(temp[i]);
  Serial.println();
}
Serial.println();
Serial.print("temp length=");
Serial.println(strlen(temp));
Serial.print("original length=");
Serial.print(strlen(original));

}
void loop() {
  // put your main code here, to run repeatedly:

}

output

temp length=37
temp length after strtok=12
i=0	b=12	:
i=1	b=13	F
i=2	b=14	r
i=3	b=15	i
i=4	b=16	 
i=5	b=17	J
i=6	b=18	u
i=7	b=19	n
i=8	b=20	 
i=9	b=21	0
i=10	b=22	1
i=11	b=23	 
i=12	b=24	2
i=13	b=25	2
i=14	b=26	:
i=15	b=27	5
i=16	b=28	5
i=17	b=29	:
i=18	b=30	5
i=19	b=31	6
i=20	b=32	 
i=21	b=33	2
i=22	b=34	0
i=23	b=35	1
i=24	b=36	8

temp length=37
original length=37

how come temp length is 37 instead of 25?

2

strtok() destroys the original string. If you need it afterwards, you'll need to make a copy before strtok() gets to it.

3

how come temp length is 37 instead of 25?

I wonder: could it be because there are 37 characters in temp[]?

4

ok and where I destroyed it ?

before destroying I copied whole string with strcpy to temp.

5

before destroying I copied whole string with strcpy to temp.

All 37 of them!

6

yes all 37 of them then

strtok(temp,":");
Serial.print("temp length after strtok=");
Serial.println(strlen(temp));

shows that strlen is 12 not 37.

SOLVED:
temp[i+1]='\0';
or b<=strlen(original) didnt notice < before

7

Go back and reread the strtok() description and find a few examples and run those. temp[] is all chopped up after strtok() so it's length is meaningless. If you don't preserve the "intermediate" strings that strtok() creates, those, too, are lost.

8

strtok() replaces the separator with a null, but then you copy it back:

for(byte i=0,b=strlen(temp);b<strlen(original);i++,b++){
    temp[i]=original[b];

original[strlen(temp)] is the separator, right?

original: abc:def
temp:     abc:def
strtok:   abc0def
strlen(temp): 3
temp[3] = original[3]: abc:def