如何在字符串中添加空字符？

Question

So I'm trying to tokenize a string without strtok for a homework assignment. The professor recommended that we add '\\0' where there is a whitespace to break the string into parts like strtok. My problem is once I find the first whitespace, I can add a '\\0' character to it, but then it stops there and I can't add '\\0' to other white space characters after that.

     int tokenize(char *line, int len){
        int i;
        char *ptr = line;
        for(i=0; i<len; i++){

           if(isspace(ptr[i]){
              ptr[i]='\0'; 

           }
        }

       return 1;
      }

     int main(){

       char *line= "wo rd ";

       int len = strlen(line);
       tokenize(line, len);

       return 1;
     }

Answer 1

Isspace function will search the string only till it encounters the NULL(\\0) character. hence compare the string elements with the space (or ASCII value) to recognize the space and replace it with a '\\0' character.

 int tokenize(char *line, int len){
        int i;
        char *ptr = line;
        for(i=0; i<len; i++){

           if(ptr[i] == ' '){
              ptr[i]='\0'; 

           }
        }

       return 1;
      }

     int main(){

       char *line= "wo rd ";

       int len = strlen(line);
       tokenize(line, len);

       return 1;
     }