解析输入线c

Question

I want to extract some numbers from the input line which is a string. The string looks like this:

    command 1 2 3 4 5

So far i've done this but it is not working properly:

   if ( strncmp(line,"command",7) == 0 ){
          char *p = strtok(line," ");
          while ( p !=NULL){
                param1 = atoi(p[1]);
                param2 = atoi(p[2]);
                param3 = atoi(p[3]);
                param4 = atoi(p[4]);
                param5 = atoi(p[5]);
                p = strtok(NULL," ");
          }
   }

Where am i wrong ?

Answer 1

Using sscanf might be simpler:

if (strncmp(line, "command", 7) == 0)
{
    sscanf(&line[8], "%d %d %d %d %d", &param1, &param2, &param3, &param4, &param5);
}

Answer 2

Why do you &p[1] ? p is a pointer to the current token in the while loop. It won't give you all the elements like you are expecting here.

You can declare param as an array: int param[5];

And rewrite the loop like:

    int i=0;
    while ( p !=NULL){
                    param[i++] = atoi(p);
                    p = strtok(NULL," ");
    }

If you want to use 5 variables like param1, param2....etc then you have to expand the loop and write it manually, not a good idea.

Answer 3

#include <string.h>
int main(){
        char line[]="command 1 2 3 4 5";
       if ( strncmp(line,"command",7) == 0 ){
              char *p = strtok(line," ");        
              while ( p !=NULL){                
            printf("%s\n",p);
                    p = strtok(NULL," ");
              }
       }
    }