关于C语言秒转时分秒程序中m赋值语句的技术疑问

Hey there! Let's break down that confusing line m = (sec -(3600*h))/60 step by step using your test input (25300 seconds) to make it concrete.

First, let's clarify what 3600*h represents:

• Since 1 hour = 3600 seconds, h is the total full hours we've already calculated from the input seconds. For 25300 seconds, h = 25300 / 3600 = 7 (because integer division in C drops the decimal part automatically).
• So 3600*h is the total number of seconds that are already accounted for by those full hours. For our test case, that's 3600*7 = 25200 seconds.

Now, let's unpack the rest of the line:

• sec - (3600*h) takes the original total seconds and subtracts the seconds we've converted to hours. This leaves us with the remaining seconds that haven't been turned into hours yet. For 25300, that's 25300 - 25200 = 100 seconds.
• Dividing that result by 60 (/60) converts those remaining seconds into full minutes. Again, using integer division, 100 / 60 = 1—which is exactly the minute value we need for the expected output.

As a side tip, you could also write this line more concisely using the modulus operator, which handles the "remaining seconds after full hours" calculation in one step:

m = (sec % 3600) / 60;

sec % 3600 gives the remainder when sec is divided by 3600, which is identical to sec - 3600*h—it's just a shorter, more idiomatic way to get the same value.

内容的提问来源于stack exchange，提问作者user479292