bash - How to change the pseudocode into real code? -

there 4 time servers, want synchronize local time ntp time server.

arr=(s2c.time.edu.cn s2d.time.edu.cn s2e.time.edu.cn s2f.time.edu.cn)  var in ${arr[@]};    # 2 lines pseudocode  here    if `ntpdate $var` secceed ,exit loop    if none of ntp time server can used,echo "failure" done 

how change pseudocode real code?
fix flaw codes:

arr=(s2c.time.edu.cn s2d.time.edu.cn s2e.time.edu.cn s2f.time.edu.cn)  switch = 0  var in ${arr[@]};    # 1 lines pseudocode  here    if `ntpdate $var` secceed ,assign switch = 1 ,exit loop done if["$switch" = "0"] ;then     echo "synchronize local time ntpdate failure" fi 

how change ifntpdate $varsecceed ,assign switch = 1 ,exit loop real bash script?

your proposed algorithm has obvious flaw:

• loop on servers
  • if ntp server can used -> exit loop
  • if none of ntp server can used -> echo failure

the flaw last step, "if none of ntp servers ...". doesn't make sense have inside loop, because cannot judge until finished loop.

consider instead:

• create function
• loop on servers
  • if ntp server can used -> return function success
• if none of ntp server can used -> return function failure

implementation:

use_any_ntp_server() {     server;        ntpdate $server && return     done     return 1 }  if ! use_any_server s2c.time.edu.cn s2d.time.edu.cn s2e.time.edu.cn s2f.time.edu.cn;     echo failure: none of ntp servers used fi