摘要：
在300处，分别打印华氏温度和摄氏温度的比较表*/intmain（）｛intfahr，Celsius；lower，upper，step；lower=0；/*温度计下限*/upper=300；/*温度上限*/step=20；/*步长*/fahr=lower；而｛Celsius=5*/9；printf；fahr=fahr+step；｝return0；｝ViewCode#include/*print华氏摄氏度=0,20，…，300；浮点版本*/intmain（）｛floatfahr，celsius；floatlower，upper，step；lower=0；/*lowerlimitftemperaturescale*/upper=300；/*上限*/step=20；/*步长*/fahr=lower；而｛celsius=*；printf；fahr=fahr+step；｝return0；｝ViewCode#include/*print华氏摄氏度=0,20，…，300；浮点版本*/intmain（）｛intfahr；forprintf；return0；｝ViewCode#include #defineLOWER0/*下限值表*/#defineUPPER300/*上限值*/#defineSTEP20/*步长*/*打印华氏摄氏度表*/intmain（）｛intfahr；forprintf；return0；｝ViewCode 2.文件复制、getchar和putchar函数#include/*copyinputtooutput；1stversion*/intmain（）｛intc；c=getchar（）；而（c！=EOF）putchar；return0；｝ViewCode 3.字符数。Double还可以自动递增#include＜stdio h＞/*countcharactersininput；1stversion*/intmain（）{longnc；nc=0；while（getchar（）！=EOF）{++nc；if++nl；ifstate=OUT；elseif{state=IN；++nw；}}printf；return0；｝ViewCode 6.统计信息、空白字符和其他字符。使用数组统计数据#include＜studio h＞/*countdigits，whites*/intmain（）｛intc，i，nwhite，otherer；intndigit[10]；nwhite=otherer=0；forndigit[i]=0；while（（c=getchar（））！=EOF）if++ndigit[c-'0']；/*countdigits*/elseif++nwhite；elseif++otherer；printf；forprintf；return0；｝ViewCode 7.幂函数幂（m，n）调用#include intpower/*testpowerfunction*/intmain（）｛inti；for(
The C Programming Language，C程序设计语言 （K&R），为C语言的设计者Dennis M. Ritchie和著名的计算机科学家Brian W．Kernighan合著的 一本介绍C语言的权威经典著作，学习c语言至今，第一次读这本书，这本书适合有一定的c语言基础的深入学习。
为什么说不适合初学者，觉得这本书更像一本字典，比如在函数章节，举例代码中用到了下面章节的数组，用到了数据结构的栈知识，为了学习大师的代码，在读这本书的时候，书中引用的代码，一一记录如下
第一章 导言
1、华氏温度与摄氏温度对照表
#include <stdio.h> /* 当 fahr=0，20，… ，300 时，分别 打印华氏温度与摄氏温度对照表 */ int main() { int fahr, celsius; int lower, upper, step; lower = 0; /* 温度表的下限 */ upper = 300; /* 温度表的上限 */ step = 20; /* 步长 */ fahr = lower; while (fahr <= upper) { celsius = 5 * (fahr-32) / 9; printf("%d %d ", fahr, celsius); fahr = fahr + step; } return 0; }
#include <stdio.h> /* print Fahrenheit-Celsius table for fahr = 0, 20, ..., 300; floating-point version */ int main() { float fahr, celsius; float lower, upper, step; lower = 0; /* lower limit of temperatuire scale */ upper = 300; /* upper limit */ step = 20; /* step size */ fahr = lower; while (fahr <= upper) { celsius = (5.0/9.0) * (fahr-32.0); printf("%3.0f %6.1f ", fahr, celsius); fahr = fahr + step; } return 0; }
#include <stdio.h> /* print Fahrenheit-Celsius table for fahr = 0, 20, ..., 300; floating-point version */ int main() { int fahr; for (fahr = 0; fahr <= 300; fahr = fahr + 20) printf("%3d %6.1f ", fahr, (5.0/9.0)*(fahr-32)); return 0; }
#include <stdio.h> #define LOWER 0 /* lower limit of table */ #define UPPER 300 /* upper limit */ #define STEP 20 /* step size */ /* print Fahrenheit-Celsius table */ int main() { int fahr; for (fahr = LOWER; fahr <= UPPER; fahr = fahr + STEP) printf("%3d %6.1f ", fahr, (5.0/9.0)*(fahr-32)); return 0; }
2、文件复制，getchar 与 putchar 函数
#include <stdio.h> /* copy input to output; 1st version */ int main() { int c; c = getchar(); while (c != EOF) { putchar(c); c = getchar(); } return 0; }
#include <stdio.h> /* copy input to output; 1st version */ int main() { int c; while ((c = getchar()) != EOF) putchar(c); return 0; }
3、字符计数，double也可以自增
#include <stdio.h> /* count characters in input; 1st version */ int main() { long nc; nc = 0; while (getchar() != EOF) ++nc; printf("%ld ", nc); return 0; }
#include <stdio.h> /* count characters in input; 2nd version */ int main() { double nc; for (nc = 0; getchar() != EOF; ++nc) ; printf("%.0f ", nc); return 0; }
4、行计数
#include <stdio.h> /* count lines in input */ int main() { int c, nl; nl = 0; while ((c = getchar()) != EOF) if (c == ' ') ++nl; printf("%d ", nl); return 0; }
5、单词计数，符号常量
#include <stdio.h> #define IN 1 /* inside a word */ #define OUT 0 /* outside a word */ /* count lines, words, and characters in input */ int main() { int c, nl, nw, nc, state; state = OUT; nl = nw = nc = 0; while ((c = getchar()) != EOF) { ++nc; if (c == ' ') ++nl; if (c == ' ' || c == ' ' || c == ' ') state = OUT; else if (state == OUT) { state = IN; ++nw; } } printf("%d %d %d ", nl, nw, nc); return 0; }
6、统计数字、空白符、其他字符，利用数组统计数字
#include <stdio.h> /* count digits, white space, others */ int main() { int c, i, nwhite, nother; int ndigit[10]; nwhite = nother = 0; for (i = 0; i < 10; ++i) ndigit[i] = 0; while ((c = getchar()) != EOF) if (c >= '0' && c <= '9') ++ndigit[c-'0']; /*count digits*/ else if (c == ' ' || c == ' ' || c == ' ') ++nwhite; else ++nother; printf("digits ="); for (i = 0; i < 10; ++i) printf(" %d", ndigit[i]); printf(", white space = %d, other = %d ", nwhite, nother); return 0; }
7、求幂的函数 power(m, n) ，传值调用
#include <stdio.h> int power(int m, int n); /* test power function */ int main() { int i; for (i = 0; i < 10; ++i) printf("%d %d %d ", i, power(2,i), power(-3,i)); return 0; } /* power: raise base to n-th power; n >= 0 */ int power(int base, int n) { int i, p; p = 1; for (i = 1; i <= n; ++i) p = p * base; return p; }
#include <stdio.h> int power(int m, int n); /* test power function */ int main() { int i; for (i = 0; i < 10; ++i) printf("%d %d %d ", i, power(2,i), power(-3,i)); return 0; } /* power: raise base to n-th power; n >= 0; version 2 */ int power(int base, int n) /*传值*/ { int p; for (p = 1; n > 0; --n) p = p * base; return p; }
8、输出最长字符串，字符数组，getline，copy，外部变量
#include <stdio.h> #define MAXLINE 1000 /* maximum input line length */ int getline(char line[], int maxline); void copy(char to[], char from[]); /* print the longest input line */ int main() { int len; /* current line length */ int max; /* maximum length seen so far */ char line[MAXLINE]; /* current input line */ char longest[MAXLINE]; /* longest line saved here */ max = 0; while ((len = getline(line, MAXLINE)) > 0) if (len > max) { max = len; copy(longest, line); } if (max > 0) /* there was a line */ printf("%s", longest); return 0; } /* getline: read a line into s, return length */ int getline(char s[],int lim) { int c, i; for (i=0; i < lim-1 && (c=getchar())!=EOF && c!=' '; ++i) s[i] = c; if (c == ' ') { /*长度包含回车符*/ s[i] = c; ++i; } s[i] = '