C segmentation fault using structures -

#include<stdio.h> #include<stdlib.h> #include<string.h> #define max_sub_commands 5 #define max_args 10 struct subcommand { char *line; char *argv[max_args]; }; struct command { struct subcommand sub_commands[max_sub_commands]; int num_sub_commands; }; void readcommand(char *line, struct command **command); void printcommand(struct command **command); void read_args(char *in, char *argv[max_args], int size); void print_args(char *argv[max_args]); int main() {     char s[200];     printf("enter command:");     fgets(s,200,stdin);     s[strlen(s)-1]='\0';     struct command *command;     readcommand(s,&command);     printcommand(&command); } void readcommand(char *line, struct command **command) {     const char *delim ="|";     const char *k;     char *copy;     char *l;     int i=0;     (*command)->num_sub_commands=0;     k=strtok(line,delim);     while(k!=null)     {         l=strdup(k);         (*command)->sub_commands[i].line=l;         printf("(*command)->sub_commands[%d].line=%s,l=%s\n",i,(*command)->sub_commands[i].line,l);         i++;         printf("%d iteration\n",i);         (*command)->num_sub_commands++;         printf("%d number of subcommands\n",(*command)->num_sub_commands);         k=strtok(null,delim);     }     (*command)->sub_commands[i].line=null;     for(i=0;(*command)->sub_commands[i].line!=null;i++)     {         copy=strdup((*command)->sub_commands[i].line);         read_args(copy,(*command)->sub_commands[i].argv,max_args);     } } void read_args(char *in, char *argv[max_args], int size) {         const char *del =" ";     int i=0;         const char *k1;         char *l1;         k1=strtok(in,del);             while(k1!=null)             {                 l1=strdup(k1);                 argv[i]=l1;                 //printf("argv[%d]=%s\n",i,argv[i]);                 i++;                 //printf("k1=%s\n",k1);                 //printf("l1=%s\n",l1);                 k1=strtok(null,del);             }     argv[i]=null; } void printcommand(struct command **command) {     int i;     for(i=0;(*command)->sub_commands[i].line!=null;i++)     {         printf("subcommand[%d]='%s' \n",i,(*command)->sub_commands[i].line);         print_args((*command)->sub_commands[i].argv);     } } void print_args(char *argv[max_args]) {     int i;     for(i=0;argv[i]!=null;i++)     {         printf("argv[%d]='%s' \n",i,argv[i]);     } } 

i getting segmentation fault, donno why? can help?? getting segmentation fault while runnig in devc++ ide , when running code on shell optimization flag o0 working fine.

i don't see in code malloc (and free).

and in main can do:

struct command command; //i don't understand why using pointers here readcommand(s,command); printcommand(command); 

and can change:

void readcommand(char *line, struct command **command); void printcommand(struct command **command); 

with:

void readcommand(char *line, struct command *command); void printcommand(struct command *command); 

and example printcommand can be:

void printcommand(struct command *command) {     int i;     for(i=0;command->sub_commands[i].line!=null;i++)     {         printf("subcommand[%d]='%s' \n",i,command->sub_commands[i].line);         print_args(command->sub_commands[i].argv);     } } 

also remember use free line , argv of subcommand struct, when finish using them.