Linux call shell

Test demo as follow: using system common

#include
#include
#include  
int main(int argc ,char *argv[])
{
    printf("system_test \n");
    system("chmod 777 ~/test/system_test/a");
}

zhuang@ubuntu:~/test/system_test$ ls -l
total 18
-rwxrwxr-x 1 zhuang zhuang 8483 Apr  1 12:55 a.out
drwxrwxrwx 2 zhuang zhuang 1024 Apr  1 13:03 b
-rwxrwxr-x 1 zhuang zhuang 8483 Apr  1 13:04 system_test
-rwxr--r-- 1 zhuang zhuang  499 Apr  1 13:03 system_test.c