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05 [C] For statement

#include <stdio.h>

/*print Farenheit-Celsius table*/

int main() {
    int fahr;

	for (fahr = 0; fahr <= 300; fahr = fahr + 20) {
		printf("%3d %6.1f\n", fahr, (5.0 / 9.0)*(fahr - 32));
	}
}

/*The C Programming Language (second edition, Prentice Hall) by Brian W. Kernighan and Dennis M. RitchieS*/

p.13


* for의 작동원리

The for statement is a loop, a generalization of the while. If you compare it to the earlier while, its operation should be clear. Within the parentheses, there are three parts, separated by semicolons. The first part, the initialization

 

fahr = 0

is done once, before the loop proper is entered. The second part is the test or condition that controls the loop:

 

fahr <= 300

This condition is evaluated; if it is true, the body of the loop (here a single printf) is executed. Then the increment step

 

fahr = fahr + 20

is executed, and the condition re-evaluated. The loop terminates if the condition has become false. As with the while, the body of the loop can be a single statement, or a group of statements enclosed in braces. The initialization, condition, and increment can be any expressions.

 

* for while문의 선택

The choice between while and for is arbitrary, based on which seems clearer. The for is usually appropriate for loops in which the initialization and increment are single statements and logically related, since it is more compact than while and it keeps the loop control statements together in one place.

 

 

[The C Programming Language (second edition, Prentice Hall) by Brian W. Kernighan and Dennis M. Ritchie, p.13]

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