,*,*,*,*,*,*,*,*,*,*,*,*,*,*,*,*,C,Chapter 21.,C,C Chapter,Chapter 21-1.,C,C,Chapter 21-1.,C,.,.,C,!,?,OS,!,OS,.,C,stdin,stdout,.,stderr,stdout,.,stdout,stderr,.,stdin,stdout,stderr,.,.,.,.,(,),.,stdin stdou,Chapter 21-2.,C,C,Chapter 21-2.,C,fputc,stdout,putchar,.,getchar,fgetc,putchar,fputc,.,putchar,.,fputc,.,.,.,fputc ,C,P,P,P,P,.,.,int,EOF,.,P,EOF,C,EOF,EOF,End Of File,.,fgetc,EOF,.,fgetc,getchar,EOF,Windows,Ctrl+Z,Linux,Ctrl+D,EOF,.,EOF,Ctrl+Z,Ctrl+D,.,.,getchar,.,EOF EOF,int,int,?,C,char,int,?,char,signed char,unsiged char,.,EOF,-1,.,char,unsigend char,EOF,-1,.,int,signed int,.,-1,.,int,int ,Chapter 21-3.,C,C,Chapter 21-3.,:puts,fputs,C,puts,fputs,!,.,fputs,.,:puts,fputs,:gets,fgets,C,.,stdin,str,sizeof(str),.,:gets,fgets ,fgets,C,1,2,3,6,.,fgets,6,.,fgets 12,Chapter 21-4.,C,C,Chapter 21-4.,C,.,.,.,.,.,.,.,fflush,C,.,.,fflush(stdout),!,.,fflush,.,fflush(stdin),.,?,fflush ,?,C,1,2,6,7,.,6,?1,Chapter 21-5.,C,C,Chapter 21-5.,:strlen,C,size_t,typedef unsigned int size_t;,typedef,:strlen s,:strcpy,strncpy,C,str1,str2,!,str1,str2,sizeof(str2),.,strcpy,.,:strcpy,strncpy,strncpy,C,str1,strncpy,.,.,strncpy ,:strcat,strncat,C,strncat,.,n,n+1,.,:strcat,strncat,:strcmp,strncmp,C,.,A,B,B,C,A,a,B,b,.,0,0,0,0,!,strncmp,n,:strcmp,strncmp,C,C,stdlib.h,int,double,.,stdlib.h,Chapter 21,.,?,Chapter 21.?,