C语言中关于getchar()的问题

显示全部楼层 · 2021-1-27 05:27:05

为何当y为int类型时scanf()后面要加两个getchar()才行，要是不加getchar()的话，后面的data的值就会等于y；加一个getchar()的话，data的值为\n；
当y为char类型时scanf()后面要加一个getchar()才行，要是不加getchar()的话，后面的data的值就会等于\n；
#include
#defineM3
intmain()
{
chara[M];
chardata;
inti,y;
intj=0;
printf("请输入：");
for(i=0;i -->

千问 · 2021-1-27 05:27:05

scanf("%d",&y);后边不跟//getchar();就会发生段错误.

千问 · 2021-1-27 05:27:05

只需一个就可以把，getchar()是为了吃掉scanf()留下的换行符啊........

千问 · 2021-1-27 05:27:05

因为printf("哈哈哈");改成
printf("哈哈哈\n");
scanf("%d",&y);
getchar();//用于接收键盘输入数字y之后的从键盘输入的回车符

千问 · 2021-1-27 05:27:05

FormatSpecificationFields:scanfandwscanfFunctions
Aformatspecificationhasthefollowingform:
%

[width][{h|l|I64|L}]type
Theformatargumentspecifiestheinterpretationoftheinputandcancontainoneormoreofthefollowing:
White-spacecharacters:blank('');tab('\t');ornewline('\n').Awhite-spacecharactercausesscanftoread,butnotstore,allconsecutivewhite-spacecharactersintheinputuptothenextnon–white-spacecharacter.Onewhite-spacecharacterintheformatmatchesanynumber(including0)andcombinationofwhite-spacecharactersintheinput.

Non–white-spacecharacters,exceptforthepercentsign(%).Anon–white-spacecharactercausesscanftoread,butnotstore,amatchingnon–white-spacecharacter.Ifthenextcharacterinstdindoesnotmatch,scanfterminates.

Formatspecifications,introducedbythepercentsign(%).Aformatspecificationcausesscanftoreadandconvertcharactersintheinputintovaluesofaspecifiedtype.Thevalueisassignedtoanargumentintheargumentlist.
Theformatisreadfromlefttoright.Charactersoutsideformatspecificationsareexpectedtomatchthesequenceofcharactersinstdin;thematchingcharactersinstdinarescannedbutnotstored.Ifacharacterinstdinconflictswiththeformatspecification,scanfterminates,andthecharacterisleftinstdinasifithadnotbeenread.

千问 · 2021-1-27 05:27:05

仅供参考：#include
intmain()
{
inta,b,n,v,r,k;
charbuf[80];
char*p;
k=0;
r=EOF;
while(1){
if(EOF==r){
fgets(buf,80,stdin);
p=buf;
}
while(1){
r=sscanf(p,"%d%n",&v,&n);
if(1==r){k++;break;}
if(EOF==r)break;
p++;
}
if(EOF==r)continue;
p+=n;
if(1==k)a=v;
if(2==k){
b=v;
break;
}
}
printf("%d,%d\n",a,b);
return0;
}
#include
chars[]="123ab4";
char*p;
intv,n,k;
voidmain(){
p=s;
while(1){
k=sscanf(p,"%d%n",&v,&n);
printf("k,v,n=%d,%d,%d\n",k,v,n);
if(1==k){
p+=n;
}elseif(0==k){
printf("skipchar[%c]\n",p[0]);
p++;
}else{//EOF==k
break;
}
}
printf("End.\n");
}
//k,v,n=1,123,3
//k,v,n=0,123,3
//skipchar[]
//k,v,n=0,123,3
//skipchar[a]
//k,v,n=0,123,3
//skipchar
//k,v,n=1,4,2
//k,v,n=-1,4,2
//End.

千问 · 2021-1-27 05:27:05

在每个最后不带\n的printf后面加fflush(stdout);
在每个不想受接收缓冲区旧内容影响的scanf前面加rewind(stdin);
另外请检查scanf的返回值。
//请今后要用
charc;
scanf("%c",&c);
//时，都改为
chars[2];
charc;
scanf("%1s",s);
c=s[0];
//自动跳过一个或多个空格或Tab字符或回车换行，读取下一个字符。