c send html reponse

char* sendHTML(char data[]){

    char str[1024] = "HTTP/1.0 200 OK\r\nContent-length:";

    char str_int[10];

    sprintf(str_int,"%d",strlen(data));

    strcat(str,str_int);

    strcat(str,"\r\n\r\n");

    strcat(str,data);

    strcat(str,"\r\n\r\n");

    char* cs=str;

    return cs;

}