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C++ 算法库(2) 修改内容的序列操作(四)

2014-11-24 08:21:27 · 作者: · 浏览: 6
标签: 算法 修改 内容 序列 操作
e_if

bool IsOdd (int i) { return ((i%2)==1); }

int main () {
int myints[] = {1,2,3,4,5,6,7,8,9}; // 1 2 3 4 5 6 7 8 9

// bounds of range:
int* pbegin = myints; // ^
int* pend = myints+sizeof(myints)/sizeof(int); // ^ ^

pend = std::remove_if (pbegin, pend, IsOdd); // 2 4 6 8
// ^ ^
std::cout << the range contains:;
for (int* p=pbegin; p!=pend; ++p)
std::cout << ' ' << *p;
std::cout << ' ';

return 0;
}

输出：

1 the range contains: 2 4 6 8

remove_copy

拷贝一个范围的元素，将其中值等价于给定值的元素删除

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18 		// remove_copy example
#include // std::cout
#include // std::remove_copy
#include // std::vector

int main () {
int myints[] = {10,20,30,30,20,10,10,20}; // 10 20 30 30 20 10 10 20
std::vector myvector (8);

std::remove_copy (myints,myints+8,myvector.begin(),20); // 10 30 30 10 10 0 0 0

std::cout << myvector contains:;
for (std::vector ::iterator it=myvector.begin(); it!=myvector.end(); ++it)
std::cout << ' ' << *it;
std::cout << ' ';

return 0;
}

输出：

1 myvector contains: 10 30 30 10 10 0 0 0

remove_copy_if

拷贝一个范围的元素，将其中值满足给定条件的元素删除

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20 		// remove_copy_if example
#include // std::cout
#include // std::remove_copy_if
#include // std::vector

bool IsOdd (int i) { return ((i%2)==1); }

int main () {
int myints[] = {1,2,3,4,5,6,7,8,9};
std::vector myvector (9);

std::remove_copy_if (myints,myints+9,myvector.begin(),IsOdd);

std::cout << myvector contains:;
for (std::vector ::iterator it=myvector.begin(); it!=myvector.end(); ++it)
std::cout << ' ' << *it;
std::cout << ' ';

return 0;
}

输出：

1 myvector contains: 2 4 6 8 0 0 0 0 0

replace

将一个范围中值等价于给定值的元素赋值为新的值

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18 		// replace algorithm example
#include // std::cout
#include // std::replace
#include // std::vector

int main () {
int myints[] = { 10, 20, 30, 30, 20, 10, 10, 20 };
std::vector myvector (myints, myints+8); // 10 20 30 30 20 10 10 20

std::replace (myvector.begin(), myvector.end(), 20, 99); // 10 99 30 30 99 10 10 99

std::cout << myvector contains:;
for (std::vector ::iterator it=myvector.begin(); it!=myvector.end(); ++it)
std::cout << ' ' << *it;
std::cout << ' ';

return 0;
}

输出：

1 myvector contains: 10 99 30 30 99 10 10 99

replace_copy

拷贝一个范围的元素，将其中值等价于给定值的元素赋值为新的值

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18 		// replace_copy example
#include // std::cout
#include // std::replace_copy
#include // std::vector

int main () {
int myints[] = { 10, 20, 30, 30, 20, 10, 10, 20 };

std::vector myvector (8);
std::replace_copy (myints, myints+8, myvector.begin(), 20, 99);

std::cout << myvector contains:;
for (std::vector ::iterator it=myvector.begin(); it!=myvector.end(); ++it)
std::cout << ' ' << *it;
std::cout << ' ';

return 0;
}

输出：

1 myvector contains: 10 99 30 30 99 10 10 99

replace_copy_if

拷贝一个范围的元素，将其中值满足给定条件的元素删除

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24 		// replace_copy_if example
#include // std::cout
#include // std::replace_copy_if
#include // std::vector

bool IsOdd (int i) { return ((i%2)==1); }

int main () {
std::vector foo,bar;

// set some values:
for (int i=1; i<10; i++) foo.push_back(i); // 1 2 3 4 5 6 7 8 9

bar.resize(foo.size()); // allocate space
std::replace_copy_if (foo.begin(), foo.end(), bar.begin(), IsOdd, 0);
// 0 2 0 4 0 6 0 8 0

std::cout << bar contains:;
for (std::vector ::iterator it=bar.begin(); it!=bar.end(); ++it)
std::cout << ' ' << *it;
std::cout << ' ';

return 0;
}

输出：

1 s