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c_programming

I study C everyday step by step with patience, passion!

Chapter 1. A Tutorial Introduction

1.1 Getting Started

ex1_1 Hello World: Very first program

#include <stdio.h>
int main(void)
{
printf("hello, world");
}

<여기서 배운 것>

• C언어에 시작할 때 Library #include stdio.h
• 라이브러리와 메인 코드 시작 전에 한 줄
• 프로그램이 실행되기 위해서는 main이 필요하다
• 프로그램 컴파일: Makefile
• 어떻게 디렉토리 분류, 커밋 메시지 남기는 지
• 커밋은 하나씩만! (한 커밋에는 하나의 내용만) https://github.com/notypicalus/c_programming/commit/1626848c392cafec0cc341908f85d3cab6b5f589
• Syntax 익숙해지기: Linux Kernel Coding Style https://www.kernel.org/doc/html/v4.10/process/coding-style.html?fbclid=IwAR2ob1ConygIGPMiyl-JcXsEf4DLp1lfmYpJh-9tBmH8cF64qBDNqnzpGko

1.2 Variables and Arithmetic Expressions

ex1_3 Modify the temperature conversion program to print a heading above the table

• Main point: int, float,
• 계산한 값을 어떻게 프린트할 수 있는지: %d, %f

ex1_4 Write a program to print the corresponding Celsius to Fahrenheit table

두 가지 방법으로 배운 화씨에서 섭씨로 변환 프로그램 Fahrenheit to °C

첫 번째:

int main()
{
  printf("A program prints Fahrenheit-Celsius\n");
  int lower, upper, step;
  int celsius, fahr;
  
  lower = 0;
  upper = 300;
  step = 20;
  
  fahr = lower;
  
  printf("화씨\t 섭씨\n");
  while(fahr <= upper)
  {
    celsius = 5 * (fahr - 32) / 9;
    printf("%d\t%d\n", fahr, celsius);
    fahr = fahr + step;
  }
  return 0;
}

두 번째:

int main()
{
  //Variable declaration

  float fahr, celsius;
  float lower, upper, step;
  
  lower = 0;
  upper = 300;
  step = 20;
  
  fahr = lower; 
  
  printf("화씨\t섭씨\n");
  while(fahr <= upper)
  {
    celsius = (5.0 / 9.0) * (fahr-32.0);
    printf("%3.0f\t%6.1f\n", fahr, celsius);
    fahr = fahr + step;
  }
}

1.3 The For Statement

ex1_5 Modify the temperature conversion program to print the table in reverse order, that is, from 300 degrees to 0

1.4 Symbolic Constants

1.5 Character Input and Output

<여기서 배운 것>

• getchar & putchar function 차이점
• buffer

1.5.1 File Copying

"The simplest example is a program that copies its input to its output one character at a time"

read a character while (character is not end-of-file indicator) output the character just read read a character

1st version:

int main()
{
    int c;

    c = getchar();
    while (c != EOF)
    {
	putchar(c);
	c = getchar();
    }
}

2nd version:

int main()
{
    int c;

    while ((c = getchar()) != EOF)
	putchar(c);
}

<여기서 배운 것>

• datatype char & int: 왜char를 사용하지 않고 int를 사용 했는 지
• EOF (end of file)

ex1_6 Verify that the expression getchar() != EOF is 0 or 1.

ex1_7 Write a program to print the value of EOF.

1.5.2 Character Counting

1st version:

int main()
{
    long nc;

    nc = 0;
    while (getchar() != EOF)
	++nc;
    printf("%ld\n", nc);
}

2nd version:

int main()
{
    double nc;
    for (nc = 0; getchar() != EOF; ++nc)
	;
    printf("%.0f\n", nc);
}

1.5.3 Line Counting

ex1_8 Write a progrma to count blanks, tabs, and newlines

ex1_9 Write a program to copy its input to output, replacing each string of one ore more blanks by a single blank.

ex1_10 Write a program to copy its input to its output, replacing each tab by /t, each backspace by /b, and each backslash by \. This makes tabs and backspaces visible in an unambiguous way.

1.5.4 Word Counting

• 참고: https://blog.naver.com/sdfgh724/221425441903

ex1_11

ex1_12

1.6 Arrays

ex1_13

ex1_14

1.7 Functions

ex1_15

1.8 Arguments--Call by Value

1.9 Character Arrays

ex1_16

ex1_17

ex1_18

ex1_19

1.10 External Variables and Scope

ex1_20

ex1_21

ex1_22

ex1_23

ex1_24

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