在C函数中使用令牌（strtok）的值

Question

I got a bit confused using token, say if:

int main(void) {
    char input[100];
    fgets(input, 100, stdin);
    char * token = strtok(input, " ");
    char * height = strtok(NULL, " ");
    char * width = strtok(NULL, " ");
    if (height > 9 && width > 9)
        set(height, width);
}

void set(char * height, char * width) {
    for (int i = 0; i < height + 1; i++) {
        for (int j = 0; j < width + 1; j++) {
            mine[i][j] = '*';
        }
    }
}

I just found that i can't use "height+1", can anyone tell me any way to use the value of height? Besides, should i put char *height and char *width in void set?

Thanks!

Answer 1

strtok() cuts the c-string into pieces and returns pointers to the delimited substrings.

So with your code, if you enter "480 640", the pointer height will point to "480" and the pointer width to "640". So they point to (ascii) strings not to integers.

If you need integers, you first have to convert them, for example with atoi() :

int main(void){
  ...
  char *token=strtok(input, " ");
  char *s_height=strtok(NULL, " "); // these are strings
  char *s_width=strtok(NULL, " ");
  int height=atoi(s_height), width=atoi(s_width); // convert to integers
  ... 
}

void set(int height, int width){
  ...
}  

Answer 2

After reading from your stream with fgets() and tokenizing it, you should convert your strings into the appropriate integer values.

char *heightStr = strtok(NULL, " ");
char *widthStr = strtok(NULL, " ");
int heightVal = atoi(heightStr);
int widthVal = atoi(widthStr);

Your set() function should also use integers as it's parameter types, not char* ie. void set(int height, int width)