Switch statement is skipped after two iterations of while loop - c

Question

I am writing a state machine for an Arduino project to parse an input string from Serial1 input. I have a switch statement in a while loop that advances the state:
char * tok = strtok(instr, " \r\n"); //instr is the input string
int state = 0;
int targx = 0, targy = 0;
while (tok)
{
// State machine:
// 0: start parsing
// 1: N2 command, parse prediction
// 2: Correct prediction, parse targx
// 3: Parse targy
// 4: Target parsing complete
// 1000: Wrong prediction / unknown command
switch (state)
{
case 0:
if (strcmp(tok, "N2") == 0) state = 1;
else if (strcmp(tok, "PANGAIN") == 0) state = 5;
else if (strcmp(tok, "TILTGAIN") == 0) state = 7;
else state = 1000;
break;
case 1:
//Look for a person
int i = strlen(tok) - 1;
while(i >= 0 && tok[i] != ':') {i--;}
if (i >= 0) tok[i] = '\0';
Serial.print("Here's what it saw: ");
Serial.print(tok);
Serial.print("\n");
if (strcmp(tok, "person") == 0)
{
state = 2;
Serial.println(state);
}
else state = 1000;
break;
case 2:
Serial.println("Inside case 2");
targx = atoi(tok);
Serial.print("Targx = ");
Serial.print(targx, DEC);
Serial.println("");
state = 3;
break;
case 3:
targy = atoi(tok);
Serial.print("Targy = ");
Serial.print(targy, DEC);
Serial.println("");
state = 4;
break;
default:
break;
}
// Move to the next token:
tok = strtok(0, " \r\n");
Serial.println(tok);
}
The problem I'm having so far is it will get to case 1 and correctly identify that "person" is in the token and set the state to 2 but on every iteration of the while loop after that, it just skips the switch statement entirely. Here's what the output looks like for one input string:
Input String: N2 person:66 -1297 -538 2431 1331
> person:66
> Here's what it saw: person
> 2
> -1297
> -538
> 2431
> 1331
Can anyone tell me why the switch statement is being bypassed entirely after case 1 is hit? Any and all help is appreciated!

Answer 1

Your if else statement in case 1 is not correct.
The first if should be like this
if (i >= 0) {tok[i] = '\0';}
You are missing the brackets.
And the else statement should also be included in brackets like this.
if (strcmp(tok, "person") == 0)
{
state = 2;
Serial.println(state);
}
else
{
state = 1000;
}
Or if it is just one line of code like yours, you could write it in a separate line.
if (strcmp(tok, "person") == 0)
{
state = 2;
Serial.println(state);
}
else
state = 1000;
Otherwise it will assign value 1000 to state, that's why the for loop would skip all the switch cases.
My English is not very good. Hope you understand it.