C ++ strtok分段错误（核心已转储）

Question

I get segmentation fault (core dumped) when I run this code.

char firstAns[80], secondAns[80];
int rs, ansLen, pipefd[2];
int pid1, pid2;
char *command1[5];
char quit[] = "quit\n";
//Asking for the commands
cout << "Please enter your first command(incl. args) or quit: ";

fgets(firstAns, 80, stdin);
//Do the program while the first answer isn't quit
if(strcmp (quit,firstAns) != 0) {
int i = 1;
command1[0] = strtok (firstAns," ");
while (command1 != NULL) {
    command1[i] = strtok (NULL, " ");       
    i++;
}

Not sure what to do here.

Answer 1

while (command1 != NULL)

is almost certainly not what you wanted to do - command1 will never be NULL/zero because it's on the stack.

I think your loop would be better written as:

int i = 0;
command1[i] = strtok (firstAns, " ");
while (command1[i] != NULL)
    command1[++i] = strtok (NULL, " ");       

This will check the correct items (the return value from the most recent strtok ) and leave i as the number of words stored.

I'd also consider making it a little more robust. As it stands now, entering five words or more will result in undefined behaviour as you write to command1[5] when the allowed indexes are 0 through 4 inclusive.