C语言函数大全(r开头).doc

计算机科学与技术社区CSTC团队资料组制作函数大全(r开头)61函数名:raise 功能:向正在执行的程序发送一个信号 用法:intraise(intsig); 程序例: #include intmain(void) inta,b; a=10; b=0; if(b=0) /*preemptdividebyzeroerror*/ raise(SIGFPE); a=a/b; return0; 函数名:rand 功能:随机数发生器 用法:voidrand(void); 程序例: #include #include intmain(void) inti; printf(Tenrandomnumbersfrom0to99nn); for(i=0;i10;i+) printf(%dn,rand()%100); return0; 函数名:randbrd 功能:随机块读 用法:intrandbrd(structfcb*fcbptr,intreccnt); 程序例: #include #include #include #include intmain(void) charfar*save_dta; charline80,buffer256; structfcbblk; inti,result; /*getuserinputfilenamefordta*/ printf(Enterdriveandfilename(nopath-i.e.a:file.dat)n); gets(line); /*putfilenameinfcb*/ if(!parsfnm(line,&blk,1) printf(Errorincalltoparsfnmn); exit(1); printf(Drive#%dFile:%snn,blk.fcb_drive,blk.fcb_name); /*openfilewithDOSFCBopenfile*/ bdosptr(0x0F,&blk,0); /*saveolddta,andsetnewone*/ save_dta=getdta(); setdta(buffer); /*setupinfoforthenewdta*/ blk.fcb_recsize=128; blk.fcb_random=0L; result=randbrd(&blk,1); /*checkresultsfromrandbrd*/ if(!result) printf(ReadOKnn); else perror(Errorduringread); exit(1); /*readindatafromthenewdta*/ printf(Thefirst128charactersare:n); for(i=0;i128;i+) putchar(bufferi); /*restorepreviousdta*/ setdta(save_dta); return0; 函数名:randbwr 功能:随机块写 用法:intrandbwr(structfcp*fcbptr,intreccnt); 程序例: #include #include #include #include intmain(void) charfar*save_dta; charline80; charbuffer256=RANDBWRtest!; structfcbblk; intresult; /*getnewfilenamefromuser*/ printf(Enterafilenametocreate(nopath-ie.a:file.datn); gets(line); /*parsethenewfilenametothedta*/ parsfnm(line,&blk,1); printf(Drive#%dFile:%sn,blk.fcb_drive,blk.fcb_name); /*requestDOSservicestocreatefile*/ if(bdosptr(0x16,&blk,0)=-1) perror(Errorcreatingfile); exit(1); /*saveolddtaandsetnewdta*/ save_dta=getdta(); setdta(buffer); /*writenewrecords*/ blk.fcb_recsize=256; blk.fcb_random=0L; result=randbwr(&blk,1); if(!result) printf(WriteOKn); else perror(Diskerror); exit(1); /*requestDOSservicestoclosethefile*/ if(bdosptr(0x10,&blk,0)=-1) perror(Errorclosingfile); exit(1); /*resettheolddta*/ setdta(save_dta); return0; 函数名:random 功能:随机数发生器 用法:intrandom(intnum); 程序例: #include #include #include /*printsarandomnumberintherange0to99*/ intmain(void) randomize(); printf(Randomnumberinthe0-99range:%dn,random(100); return0; 函数名:randomize 功能:初始化随机数发生器 用法:voidrandomize(void); 程序例: #include #include #include intmain(void) inti; randomize(); printf(Tenrandomnumbersfrom0to99nn); for(i=0;i10;i+) printf(%dn,rand()%100); return0; 函数名:read 功能:从文件中读 用法:intread(inthandle,void*buf,intnbyte); 程序例: #include #include #include #include #include #include intmain(void) void*buf; inthandle,bytes; buf=malloc(10); /* LooksforafileinthecurrentdirectorynamedTEST.$andattempts toread10bytesfromit.Tousethisexampleyoushouldcreatethe fileTEST.$ */ if(handle= open(TEST.$,O_RDONLY|O_BINARY,S_IWRITE|S_IREAD)=-1) printf(ErrorOpeningFilen); exit(1); if(bytes=read(handle,buf,10)=-1) printf(ReadFailed.n); exit(1); else printf(Read:%dbytesread.n,bytes); return0; 函数名:realloc 功能:重新分配主存 用法:void*realloc(void*ptr,unsignednewsize); 程序例: #include #include #include intmain(void) char*str; /*allocatememoryforstring*/ str=malloc(10); /*copyHellointostring*/ strcpy(str,Hello); printf(Stringis%snAddressis%pn,str,str); str=realloc(str,20); printf(Stringis%snNewaddressis%pn,str,str); /*freememory*/ free(str); return0; 函数名:rectangle 功能:画一个矩形 用法:voidfarrectangle(intleft,inttop,intright,intbottom); 程序例: #include #include #include #include intmain(void) /*requestautodetection*/ intgdriver=DETECT,gmode,errorcode; intleft,top,right,bottom; /*initializegraphicsandlocalvariables*/ initgraph(&gdriver,&gmode,); /*readresultofinitialization*/ errorcode=graphresult(); if(errorcode!=grOk)/*anerroroccurred*/ printf(Graphicserror:%sn,grapherrormsg(errorcode); printf(Pressanykeytohalt:); getch(); exit(1);/*terminatewithanerrorcode*/ left=getmaxx()/2-50; top=getmaxy()/2-50; right=getmaxx()/2+50; bottom=getmaxy()/2+50; /*drawarectangle*/ rectangle(left,top,right,bottom); /*cleanup*/ getch(); closegraph(); return0; 函数名:registerbgidriver 功能:登录已连接进来的图形驱动程序代码 用法:intregisterbgidriver(void(*driver)(void); 程序例: #include #include #include #include intmain(void) /*requestautodetection*/ intgdriver=DETECT,gmode,errorcode; /*registeradriverthatwasaddedintographics.lib*/ errorcode=registerbgidriver(EGAVGA_driver); /*reportanyregistrationerrors*/ if(errorcode0) printf(Graphicserror:%sn,grapherrormsg(errorcode); printf(Pressanykeytohalt:); getch(); exit(1);/*terminatewithanerrorcode*/ /*initializegraphicsandlocalvariables*/ initgraph(&gdriver,&gmode,); /*readresultofinitialization*/ errorcode=graphresult(); if(errorcode!=grOk)/*anerroroccurred*/ printf(Graphicserror:%sn,grapherrormsg(errorcode); printf(Pressanykeytohalt:); getch(); exit(1);/*terminatewithanerrorcode*/ /*drawaline*/ line(0,0,getmaxx(),getmaxy(); /*cleanup*/ getch(); closegraph(); return0; 函数名:remove 功能:删除一个文件 用法:intremove(char*filename); 程序例: #include intmain(void) charfile80; /*promptforfilenametodelete*/ printf(Filetodelete:); gets(file); /*deletethefile*/ if(remove(file)=0) printf(Removed%s.n,file); else perror(remove); return0; 函数名:rename 功能:重命名文件 用法:intrename(char*oldname,char*newname); 程序例: #include intmain(void) charoldname80,newname80; /*promptforfiletorenameandnewname*/ printf(Filetorename:); gets(oldname); printf(Newname:); gets(newname); /*Renamethefile*/ if(rename(oldname,newname)=0) printf(Renamed%sto%s.n,oldname,newname); else perror(rename); return0; 函数名:restorecrtmode 功能:将屏幕模式恢复为先前的imitgraph设置 用法:voidfarrestorecrtmode(void); 程序例: #include #include #include #include intmain(void) /*requestautodetection*/ intgdriver=DETECT,gmode,errorcode; intx,y; /*initializegraphicsandlocalvariables*/ initgraph(&gdriver,&gmode,); /*readresultofinitialization*/ errorcode=graphresult(); if(errorcode!=grOk)/*anerroroccurred*/ printf(Graphicserror:%sn,grapherrormsg(errorcode); printf(Pressanykeytohalt:); getch(); exit(1);/*terminatewithanerrorcode*/ x=getmaxx()/2; y=getmaxy()/2; /*outputamessage*/ settextjustify(CENTER_TEXT,CENTER_TEXT); outtextxy(x,y,Pressanykeytoexitgraphics:); getch(); /*restoresystemtotextmode*/ restorecrtmode(); printf(Werenowintextmode.n); printf(Pressanykeytoreturntographicsmode:); getch(); /*returntographicsmode*/ setgraphmode(getgraphmode(); /*outputamessage*/ settextjustify(CENTER_TEXT,CENTER_TEXT); outtextxy(x,y,Werebackingraphicsmode.); outtextxy(x,y+textheight(W),Pressanykeytohalt:); /*cleanup*/ getch(); closegraph(); return0; 函数名:rewind 功能:将文件指针重新指向一个流的开头 用法:intrewind(FILE*stream); 程序例: #include #