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190+ 最終更新日時(UTC):
191+ < span itemprop ="datePublished " content ="2025-07-11T02:42:04 ">
192+ 2025年07月11日 02時42分04秒
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198+ が更新
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204+ < span class ="fa fa-fw fa-clock-o fa-flip-horizontal "> </ span > 履歴
205+ </ a >
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207+ < span class ="fa fa-fw fa-pencil "> </ span > 編集
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214+
215+ < div class ="identifier-type "> function</ div > < div class ="header "> <cstdio></ div > < h1 itemprop ="name "> < span class ="namespace " title ="namespace std "> std::</ span > < span class ="token "> ungetc</ span > </ h1 >
216+ < div itemprop ="articleBody "> < p > < div class ="codehilite "> < pre > < span > </ span > < code > < span class ="kt "> int</ span > < span class ="nf "> ungetc</ span > < span class ="p "> (</ span > < span class ="kt "> int</ span > < span class ="n "> c</ span > < span class ="p "> ,</ span > < span class ="kt "> FILE</ span > < span class ="o "> *</ span > < span class ="n "> stream</ span > < span class ="p "> );</ span >
217+ </ code > </ pre > </ div >
218+ </ p >
219+ < h2 > 概要</ h2 >
220+ < p > 符号なしの文字< code > c</ code > を入力ストリーム< code > stream</ code > に戻す。</ p >
221+ < p > この関数は、連続してこの関数が呼び出される場合、入力ストリームへのプッシュ・バックを保証できる連続した文字は 1 つのみである。</ p >
222+ < p > また、< code > c</ code > は< code > < a href ="eof.html "> EOF</ a > </ code > であってはならない。</ p >
223+ < p > この関数が呼び出されたのち、< code > < span href ="https://cpprefjp.github.io/reference/cstdio/fseek.md.nolink "> fseek</ span > </ code > や< code > < span href ="https://cpprefjp.github.io/reference/cstdio/fsetpos.md.nolink "> fsetpos</ span > </ code > 、< code > < span href ="https://cpprefjp.github.io/reference/cstdio/rewind.md.nolink "> rewind</ span > </ code > 、< code > < a href ="fflush.html "> fflush</ a > </ code > を呼び出すと、その関数の呼び出しによって戻された文字は失われる。</ p >
224+ < h2 > < a class ="cpprefjp-defined-word " data-desc ="関数呼び出し式の評価結果となるオブジェクト・値 "> 戻り値</ a > </ h2 >
225+ < p > 成功したら挿入した< code > c</ code > を、そうでなければ< code > < a href ="eof.html "> EOF</ a > </ code > を返す。</ p >
226+ < h2 > 例</ h2 >
227+ < p > < div class ="yata " id ="5af1df06287e4348fc9c2fa3bcf27b756071526a "> < div class ="codehilite "> < pre > < span > </ span > < code > < span class ="cp "> #include</ span > < span class ="cpf "> < a href ="../cstdio.html "> <cstdio></ a > </ span > < span class ="cp "> </ span >
228+
229+ < span class ="kt "> int</ span > < span class ="nf "> main</ span > < span class ="p "> ()</ span > < span class ="p "> {</ span >
230+ < span class ="n "> < a href ="putchar.html "> putchar</ a > </ span > < span class ="p "> (</ span > < span class ="n "> < a href ="getchar.html "> getchar</ a > </ span > < span class ="p "> ());</ span >
231+ < span class ="n "> < span style ="color:#ff0000 "> ungetc</ span > </ span > < span class ="p "> (</ span > < span class ="sc "> 'A'</ span > < span class ="p "> ,</ span > < span class ="n "> stdin</ span > < span class ="p "> );</ span >
232+ < span class ="n "> < a href ="putchar.html "> putchar</ a > </ span > < span class ="p "> (</ span > < span class ="n "> < a href ="getchar.html "> getchar</ a > </ span > < span class ="p "> ());</ span >
233+ < span class ="p "> }</ span >
234+ </ code > </ pre > </ div >
235+ </ div > </ p >
236+ < h3 > 入力</ h3 >
237+ < p > < pre > < code > a
238+ </ code > </ pre > </ p >
239+ < h3 > 出力</ h3 >
240+ < p > < pre > < code > aA
241+ </ code > </ pre > </ p >
242+ < h2 > 処理系</ h2 >
243+ < ul >
244+ < li > < a href ="../../implementation.html#clang "> Clang</ a > : ??</ li >
245+ < li > < a href ="../../implementation.html#gcc "> GCC</ a > : ??</ li >
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