c++ stl bitset 位图操作

最新推荐文章于 2024-02-15 20:10:24 发布

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本文介绍了如何使用C++的bitset和文件操作来生成和读取大量的数字序列，展示了在内存有限的情况下高效地存储和检索整数的方法。

/*
* bitset.cpp
*
* Created on: 2013-1-1
* Author: Administrator
*/

#include<time.h>
#include<stdio.h>
#include<stdlib.h>
#include<bitset>
#include<iostream>
#include<limits.h>

using namespace std;

#define MAX_SIZE 1000000
void write_number() {
FILE * fh = fopen("./data/digit.txt", "a");
if (fh) {
srand((int) time(0));
for (int i = 0; i < 10; i++) {
int num = rand()%MAX_SIZE;
fprintf(fh, "%d\n", num);
}
fclose(fh);
}

}

void read_number() {
FILE * fh = fopen("./data/digit.txt", "r");
if (fh) {
int num;
while (EOF != fscanf(fh, "%d", &num)) {
printf("%d\n", num);
}
fclose(fh);
}

}
int main() {

cout<<INT_MAX<<" ";
write_number();
read_number();
bitset<MAX_SIZE> bitmap;
bitmap.reset();

FILE * fh = fopen("./data/digit.txt", "r");
if (fh) {
int num;
while (EOF != fscanf(fh, "%d", &num)) {
cout<<num<<" ";
bitmap[num] = 1;
}
fclose(fh);
}
for (int i = 0; i < MAX_SIZE; i++) {

if (bitmap[i] == 1) {
cout << i << ",";
}
}

return 0;
}