strcat causing string to become empty

I have the following code where strcat is causing problem.

Code:

      char* tokens = strtok(buf, "+");
      int n = 0;
      int type = 0;
      char* name = "";
      char* lifetime = "";
      char* data = "";
      for(n=0; tokens!=NULL; n++) {
          if(n==0)
            type = atoi(tokens);
          if(n==1)
            name = tokens;
          if(n == 2) {
             if(type == 1)
                lifetime = tokens;
             else
                data = tokens;
          }
          if(n == 3)
             lifetime = tokens;
          tokens = strtok(NULL, "+");
      }


      if(type == 2) {
         printf("Received Data with Name: %s, Data: \"%s\" and lifetime: %s seconds\n", name, data, lifetime);

         strncat(name, "+", 1);
         printf("Data: %s\n", data);
         strncat(name, data, strlen(data));
         printf("Full Name: %s\n", name);
      }

In the line where I print the name, data and lifetime everything prints correctly. But after the strcat operations I find that "data" value is empty. After adding debug printf statements I have found that "data" value becomes empty right after

Code:

strncat(name,"+",1)

What could be the reason? Please help.

Code:

char* name = "";

this makes name a string literal. you cannot append anything to that.
try a char array.
kurt

C strings are static arrays of chars, they don't grow or shrink dynamically. Your variable name, is just a pointer you can not use strcat to add characters to it.