for loops execution

Question

can the following loop be executed for(j=0;i=len-1;i>=0;i--;j++) and if yes please tell me how the execution procedure?

Answer 1

You really need to clarify your question. For instance, what language is this? (I've never heard of a language called "deep".)

If it's C, C++, Java, JavaScript, or one of the related languages, your syntax is slightly wrong (the first and last semicolons should be commas):

for (j = 0, i = len - 1; i >= 0; i--, j++) {
     // Do something
}

...and yes, the body of the loop would run at least once if len is greater than zero. (It will run as many times as the value len, e.g., twice if len = 2, three times if len = 3.) Try it!

Answer 2

I don't know a single language where this would be a valid syntax. If you're talking about C, C++, C#, Java, JavaScript, PHP, or Objective C, no, it will not execute. Won't even compile. The following, however, will:

for(j=0, i=len-1; i>=0; i--, j++) 

Note the commas instead of semicolons. On each iteration i will decrease and j will increase.