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@7shi 7shi/sparse.cpp
Created Mar 7, 2014

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[C++]スパースファイルの実験
#include <stdio.h>
int main() {
// 10バイトのファイルを作成
char a[10] = {0};
FILE *f = fopen("test", "wb");
fwrite(a, 1, sizeof(a), f);
fclose(f);
f = fopen("test", "r+b");
// 100バイト目にシーク(範囲外だがOK)
fseek(f, 100, SEEK_SET);
// 読み込み(失敗)
printf("%d\n", fread(a, 1, sizeof(a), f));
// 書き込み(成功) → ファイルサイズが110バイトになる
printf("%d\n", fwrite(a, 1, sizeof(a), f));
fclose(f);
}
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