c - Issue with array manipulation and memset -

i have c program reads characters stdin (using getchar) until blank line read, , null element added , characters read before blank line sent execve. then, more characters read , added same array (which i'm trying reset after first call execve) until blank line read, , second section should executed. having trouble using memset reset array after each call execve , working args[i] = null can pass array execve.

e.g. usage:

echo

hello

after seeing blank line executes "echo hello"

cat

goodbye

*should cat file "goodbye" when first 2 arguments "echo" , "null"

int main() {   int pid, status, c, size = 10, length = 0, i, blankflag = 0, alrdyexec = 0;   char argument[1000];   char **args;   char *token;   args = (char**)malloc(size);   extern int process(char **args);   fflush(stdout);  while ((c = getchar()) != eof) {     if (length == size) {         size += 10;         args = realloc(args, size);     }     if (c != '\n') {         argument[length++] = c;         blankflag = 0;         alrdyexec = 0;     } else if ((c == '\n') && (blankflag == 0)) {         blankflag = 1;         argument[length++] = c;     } else if ((c == '\n') && (blankflag == 1) && (alrdyexec == 0)) {         alrdyexec = 1;         = 0;         memset(args, 0, sizeof(args));         token = strtok(argument, "\n");         while (token != null) {             args[i] = token;             token = strtok(null, "\n");             i++;         }         args[i] = null;         // here executes function runs execve         }         }     return(0); }