整数値からｎ桁文字列に変換する関数群をまとめたページです。(戻る)
アルゴリズム
整数値から文字列に変換する場合は、整数値の下位桁から[0]～[35]の余りを解読してきます。
余りは普通に36で割って求めます。(％演算)
なお、基数が２の倍数である 2進数、8進数、16進数はビット論理積を使って余りを求めます。
この方がちょっとだけ高速になります。(最新のパソコンでは高速化してるのか良く分からないね)
しかし、このままでは文字列が左右反転してるので戻すために左右並びを反転させます。
このときに出力桁数分だけスペース文字などを文字列バッファ(lpBuff)にコピーします。
こうすることで文字列バッファ(lpBuff)の先頭に出力桁数に見合うスペース文字で埋められます。
なお、スペース文字の代わりに[0]の文字で埋めたり、接頭語(0b、0o、0d、0x)もコピーするように改良も可能です。
接頭語(0b、0o、0d、0x)を出力するときには[x][0]の順にコピーしたり、出力桁数から２文字分だけ引いた残りが
スペース文字(ゼロ文字)で埋める出力桁数になることに気をつけましょう。
今回は接頭語(0b、0o、0d、0x)は出力しません。
//------------------------------------------------ // 関数のプロトタイプ宣言 //------------------------------------------------ extern LPTSTR funcIntToBinEx( LPTSTR lpBuff, UINT nValue, LONG nWidth, TCHAR tcSpace ); extern LPTSTR funcIntToOctEx( LPTSTR lpBuff, UINT nValue, LONG nWidth, TCHAR tcSpace ); extern LPTSTR funcIntToHexEx( LPTSTR lpBuff, UINT nValue, LONG nWidth, TCHAR tcSpace ); extern LPTSTR funcIntToDecEx( LPTSTR lpBuff, UINT nValue, LONG nWidth, TCHAR tcSpace ); extern LPTSTR funcIntToStrEx( LPTSTR lpBuff, UINT nValue, LONG nWidth, TCHAR tcSpace, LONG nRadix );
サンプル
//------------------------------------------------------------------------------
// 整数値から2進/8進/10進/16進文字列に変換
//------------------------------------------------------------------------------
#include <stdio.h>
#include <tchar.h>
#include <locale.h>
#include <Windows.h>
//------------------------------------------------
// 文字列の左右並びを反転
//------------------------------------------------
static VOID funcStrReverseEx( LPTSTR lpHead, LPTSTR lpTail, LONG nWidth, TCHAR tcSpace )
{
TCHAR tcSwap[ 1 ];
while ( nWidth > 0 ){
nWidth--; *lpTail++ = tcSpace;
}
for ( *lpTail-- = TEXT('\0') ; lpHead < lpTail ; lpHead++, lpTail-- ){
tcSwap[ 0 ] = lpHead[ 0 ];
lpHead[ 0 ] = lpTail[ 0 ];
lpTail[ 0 ] = tcSwap[ 0 ];
}
}
//------------------------------------------------
// 整数値からｎ桁2進文字列に変換
//------------------------------------------------
extern LPTSTR funcIntToBinEx( LPTSTR lpBuff, UINT nValue, LONG nWidth, TCHAR tcSpace )
{
LPTSTR lpTail = lpBuff;
if ( nValue == 0 ){
nWidth--; *lpTail++ = TEXT('0');
}
else for ( ; nValue ; nValue >>= 1 ){
nWidth--; *lpTail++ = ((nValue & 0x1) + TEXT('0'));
}
funcStrReverseEx( lpBuff, lpTail, nWidth, tcSpace );
return lpBuff;
}
//------------------------------------------------
// 整数値からｎ桁8進文字列に変換
//------------------------------------------------
extern LPTSTR funcIntToOctEx( LPTSTR lpBuff, UINT nValue, LONG nWidth, TCHAR tcSpace )
{
LPTSTR lpTail = lpBuff;
if ( nValue == 0 ){
nWidth--; *lpTail++ = TEXT('0');
}
else for ( ; nValue ; nValue >>= 3 ){
nWidth--; *lpTail++ = ((nValue & 0x7) + TEXT('0'));
}
funcStrReverseEx( lpBuff, lpTail, nWidth, tcSpace );
return lpBuff;
}
//------------------------------------------------
// 整数値からｎ桁16進文字列に変換
//------------------------------------------------
extern LPTSTR funcIntToHexEx( LPTSTR lpBuff, UINT nValue, LONG nWidth, TCHAR tcSpace )
{
LPTSTR lpTail = lpBuff;
if ( nValue == 0 ){
nWidth--; *lpTail++ = TEXT('0');
}
else for ( ; nValue ; nValue >>= 4 ){
nWidth--; *lpTail++ = TEXT("0123456789ABCDEF")[ nValue & 0xF ];
}
funcStrReverseEx( lpBuff, lpTail, nWidth, tcSpace );
return lpBuff;
}
//------------------------------------------------
// 整数値からｎ桁10進文字列に変換
//------------------------------------------------
extern LPTSTR funcIntToDecEx( LPTSTR lpBuff, UINT nValue, LONG nWidth, TCHAR tcSpace )
{
LPTSTR lpTail = lpBuff;
if ( nValue == 0 ){
nWidth--; *lpTail++ = TEXT('0');
}
else for ( ; nValue ; nValue /= 10 ){
nWidth--; *lpTail++ = ((nValue % 10) + TEXT('0'));
}
funcStrReverseEx( lpBuff, lpTail, nWidth, tcSpace );
return lpBuff;
}
//------------------------------------------------
// 整数値からｎ桁ｎ進文字列に変換
//------------------------------------------------
extern LPTSTR funcIntToStrEx( LPTSTR lpBuff, UINT nValue, LONG nWidth, TCHAR tcSpace, LONG nRadix )
{
LPTSTR lpTable;
LPTSTR lpTail = lpBuff;
if ( nRadix < 0 ){
nRadix = -nRadix;
lpTable = TEXT("0123456789abcdefghijklmnopqrstuvwxyz");
}
else{
lpTable = TEXT("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ");
}
if ( nValue == 0 ){
nWidth--; *lpTail++ = TEXT('0');
}
else for ( ; nValue ; nValue /= nRadix ){
nWidth--; *lpTail++ = lpTable[ nValue % nRadix ];
}
funcStrReverseEx( lpBuff, lpTail, nWidth, tcSpace );
return lpBuff;
}
//------------------------------------------------
// メイン関数
//------------------------------------------------
int _tmain( void )
{
TCHAR szBuff[ 256 ];
LONG nValue;
LONG nWidth = 8;
TCHAR tcSpace = TEXT('0');
_tsetlocale( LC_ALL, TEXT("") );
_tprintf( TEXT("\n// 整数値から2進文字列に変換\n") );
for ( nValue = 0 ; nValue < 32 ; nValue++ ){
_tprintf( TEXT("%2ld = [%s]\n"), nValue, funcIntToBinEx(szBuff,nValue,nWidth,tcSpace) );
}
_tprintf( TEXT("\n// 整数値から8進文字列に変換\n") );
for ( nValue = 0 ; nValue < 32 ; nValue++ ){
_tprintf( TEXT("%2ld = [%s]\n"), nValue, funcIntToOctEx(szBuff,nValue,nWidth,tcSpace) );
}
_tprintf( TEXT("\n// 整数値から10進文字列に変換\n") );
for ( nValue = 0 ; nValue < 32 ; nValue++ ){
_tprintf( TEXT("%2ld = [%s]\n"), nValue, funcIntToDecEx(szBuff,nValue,nWidth,tcSpace) );
}
_tprintf( TEXT("\n// 整数値から16進文字列に変換\n") );
for ( nValue = 0 ; nValue < 32 ; nValue++ ){
_tprintf( TEXT("%2ld = [%s]\n"), nValue, funcIntToHexEx(szBuff,nValue,nWidth,tcSpace) );
}
_tprintf( TEXT("\n// 整数値からｎ進文字列に変換(大文字)\n") );
for ( nValue = 0 ; nValue < 32 ; nValue++ ){
_tprintf( TEXT("%2ld = [%s]\n"), nValue, funcIntToStrEx(szBuff,nValue,nWidth,tcSpace,+16) );
}
_tprintf( TEXT("\n// 整数値からｎ進文字列に変換(小文字)\n") );
for ( nValue = 0 ; nValue < 32 ; nValue++ ){
_tprintf( TEXT("%2ld = [%s]\n"), nValue, funcIntToStrEx(szBuff,nValue,nWidth,tcSpace,-16) );
}
return 0;
}
//------------------------------------------------------------------------------
// End of funcIntToStrLibEx.cpp
//------------------------------------------------------------------------------
実行結果
// 整数値から2進文字列に変換 0 = [00000000] 1 = [00000001] 2 = [00000010] 3 = [00000011] 4 = [00000100] 5 = [00000101] 6 = [00000110] 7 = [00000111] 8 = [00001000] 9 = [00001001] 10 = [00001010] 11 = [00001011] 12 = [00001100] 13 = [00001101] 14 = [00001110] 15 = [00001111] 16 = [00010000] 17 = [00010001] 18 = [00010010] 19 = [00010011] 20 = [00010100] 21 = [00010101] 22 = [00010110] 23 = [00010111] 24 = [00011000] 25 = [00011001] 26 = [00011010] 27 = [00011011] 28 = [00011100] 29 = [00011101] 30 = [00011110] 31 = [00011111] // 整数値から8進文字列に変換 0 = [00000000] 1 = [00000001] 2 = [00000002] 3 = [00000003] 4 = [00000004] 5 = [00000005] 6 = [00000006] 7 = [00000007] 8 = [00000010] 9 = [00000011] 10 = [00000012] 11 = [00000013] 12 = [00000014] 13 = [00000015] 14 = [00000016] 15 = [00000017] 16 = [00000020] 17 = [00000021] 18 = [00000022] 19 = [00000023] 20 = [00000024] 21 = [00000025] 22 = [00000026] 23 = [00000027] 24 = [00000030] 25 = [00000031] 26 = [00000032] 27 = [00000033] 28 = [00000034] 29 = [00000035] 30 = [00000036] 31 = [00000037] // 整数値から10進文字列に変換 0 = [00000000] 1 = [00000001] 2 = [00000002] 3 = [00000003] 4 = [00000004] 5 = [00000005] 6 = [00000006] 7 = [00000007] 8 = [00000008] 9 = [00000009] 10 = [00000010] 11 = [00000011] 12 = [00000012] 13 = [00000013] 14 = [00000014] 15 = [00000015] 16 = [00000016] 17 = [00000017] 18 = [00000018] 19 = [00000019] 20 = [00000020] 21 = [00000021] 22 = [00000022] 23 = [00000023] 24 = [00000024] 25 = [00000025] 26 = [00000026] 27 = [00000027] 28 = [00000028] 29 = [00000029] 30 = [00000030] 31 = [00000031] // 整数値から16進文字列に変換 0 = [00000000] 1 = [00000001] 2 = [00000002] 3 = [00000003] 4 = [00000004] 5 = [00000005] 6 = [00000006] 7 = [00000007] 8 = [00000008] 9 = [00000009] 10 = [0000000A] 11 = [0000000B] 12 = [0000000C] 13 = [0000000D] 14 = [0000000E] 15 = [0000000F] 16 = [00000010] 17 = [00000011] 18 = [00000012] 19 = [00000013] 20 = [00000014] 21 = [00000015] 22 = [00000016] 23 = [00000017] 24 = [00000018] 25 = [00000019] 26 = [0000001A] 27 = [0000001B] 28 = [0000001C] 29 = [0000001D] 30 = [0000001E] 31 = [0000001F] // 整数値からｎ進文字列に変換(大文字) 0 = [00000000] 1 = [00000001] 2 = [00000002] 3 = [00000003] 4 = [00000004] 5 = [00000005] 6 = [00000006] 7 = [00000007] 8 = [00000008] 9 = [00000009] 10 = [0000000A] 11 = [0000000B] 12 = [0000000C] 13 = [0000000D] 14 = [0000000E] 15 = [0000000F] 16 = [00000010] 17 = [00000011] 18 = [00000012] 19 = [00000013] 20 = [00000014] 21 = [00000015] 22 = [00000016] 23 = [00000017] 24 = [00000018] 25 = [00000019] 26 = [0000001A] 27 = [0000001B] 28 = [0000001C] 29 = [0000001D] 30 = [0000001E] 31 = [0000001F] // 整数値からｎ進文字列に変換(小文字) 0 = [00000000] 1 = [00000001] 2 = [00000002] 3 = [00000003] 4 = [00000004] 5 = [00000005] 6 = [00000006] 7 = [00000007] 8 = [00000008] 9 = [00000009] 10 = [0000000a] 11 = [0000000b] 12 = [0000000c] 13 = [0000000d] 14 = [0000000e] 15 = [0000000f] 16 = [00000010] 17 = [00000011] 18 = [00000012] 19 = [00000013] 20 = [00000014] 21 = [00000015] 22 = [00000016] 23 = [00000017] 24 = [00000018] 25 = [00000019] 26 = [0000001a] 27 = [0000001b] 28 = [0000001c] 29 = [0000001d] 30 = [0000001e] 31 = [0000001f]［←前へ］ ［目次］ ［次へ→］
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