怎么学习网站开发,怎么进成品网站后台,2023免费推广入口,机械设备行业网站建设目录 1.c_str() 返回C常量字符串
2.date() 返回C常量字符串
3.substr() 构造子串
4.find() 正向查找#xff08;查找失败返回npos#xff09;
5.rfind() 逆向查找#xff08;查找失败返回npos#xff09;
6.find_first_of() 正向查找匹配的字符
7.find_last_of() 逆向…目录 1.c_str() 返回C常量字符串
2.date() 返回C常量字符串
3.substr() 构造子串
4.find() 正向查找查找失败返回npos
5.rfind() 逆向查找查找失败返回npos
6.find_first_of() 正向查找匹配的字符
7.find_last_of() 逆向查找匹配的字符
8.find_first_not_of() 正向查找不匹配的字符
9.find_last_not_of() 逆向查找不匹配的字符
10.compare() 比较字符串 1.c_str() 返回C常量字符串
const char* c_str() const
string s(123);
const char* p s.c_str();
cout p endl;//1232.date() 返回C常量字符串
const char* data() const
string s(12345);
const char* p s.data();
cout p endl;//12345
3.substr() 构造子串
string substr(size_t pos 0, size_t len npos) const
返回pos位置开始的len个字符组成的字符串
string s1 12345;
string s2 s1.substr(2, 3);
cout s2 endl;//345
4.find() 正向查找查找失败返回npos
string (1) size_t find (const string str, size_t pos 0) const;c-string (2) size_t find (const char* s, size_t pos 0) const;buffer (3) size_t find (const char* s, size_t pos, size_t n) const;character (4) size_t find (char c, size_t pos 0) const;
1.size_t find(const string str, size_t pos 0) const
从pos位置开始查找匹配的对象str返回查找到的位置
2.size_t find(const char* s, size_t pos 0) const
从pos位置开始查找匹配的字符串s返回查找到的位置
3.size_t find(const char* s, size_t pos, size_t n)
从pos位置查找匹配字符串s的前n个字符返回查找到的位置
4.size_t find(char c, size_t pos 0)
从pos位置开始查找字符c返回查找到的位置
string s1(There are two needles in this haystack with needles.);
string s2(needle);
size_t found s1.find(s2, 0);
if (found ! string::npos)
{cout first needle found at found endl;//first needle found at 14
}
else
{cout needle no found endl;
}found s1.find(needle are small, found 1, 6);
if (found ! string::npos)
{cout second needle found at found endl;//second needle found at 44
}
else
{cout needle no found endl;
}found s1.find(haystack, 0);
if (found ! string::npos)
{cout haystack found at found endl;//haystack found at 30
}
else
{cout haystack no found endl;
}found s1.find(., 0);
if (found ! string::npos)
{cout . found at found endl;//. found at 30
}
else
{cout . no found endl;
}
5.rfind() 逆向查找查找失败返回npos
string (1) size_t rfind (const string str, size_t pos npos) const;c-string (2) size_t rfind (const char* s, size_t pos npos) const;buffer (3) size_t rfind (const char* s, size_t pos, size_t n) const;character (4) size_t rfind (char c, size_t pos npos) const;
1.size_t rfind(const string str, size_t pos npos) const
从pos位置逆向开始查找匹配的对象str返回查找到的位置
2.size_t rfind(const char* s, size_t pos npos) const
从pos位置逆向开始查找匹配的字符串s返回查找到的位置
3.size_t rfind(const char* s, size_t pos, size_t n) const
从pos位置逆向查找匹配字符串s的前n个字符返回查找到的位置
4.size_t rfind(char c, size_t pos npos) const
从pos位置逆向开始查找字符c返回查找到的位置
string str(The sixth sick sheiks sixth sheeps sick.);
string key(sixth);
size_t found str.rfind(key);
if (found ! string::npos)cout sixth found at found endl;//sixth found at 23
6.find_first_of() 正向查找匹配的字符
正向查找首个与指定字符串中任一字符匹配的字符查找失败返回npos
string (1) size_t find_first_of (const string str, size_t pos 0) const;c-string (2) size_t find_first_of (const char* s, size_t pos 0) const;buffer (3) size_t find_first_of (const char* s, size_t pos, size_t n) const;character (4) size_t find_first_of (char c, size_t pos 0) const;
1.size_t find_first_of(const string str, size_t pos 0) const
从pos位置开始查找对象str中首次出现的任一字符查找失败返回npos
2.size_t find_first_of(const char* s, size_t pos 0) const
从pos位置开始查找字符串s中出现的任一字符查找失败返回npos
3.size_t find_first_of(const char* s, size_t pos, size_t n) const
从pos位置开始查找字符串s的前n个字符串中出现的任一字符查找失败返回npos
4.size_t find_first_of(char c, size_t pos 0 ) const
从pos位置开始查找首次出现的字符c查找失败返回npos
string s(Please, replace the vowels in this sentence by asterisks.);
size_t found s.find_first_of(aoeiu, 0);
while (found ! string::npos)
{s[found] *;found s.find_first_of(aoeiu, found 1);
}
cout s endl;//Pl**s*, r*pl*c* th* v*w*ls *n th*s s*nt*nc* by *st*r*sks.
7.find_last_of() 逆向查找匹配的字符
逆向查找首个与指定字符串中任一字符匹配的字符查找失败返回npos
string (1) size_t find_last_of (const string str, size_t pos npos) const;c-string (2) size_t find_last_of (const char* s, size_t pos npos) const;buffer (3) size_t find_last_of (const char* s, size_t pos, size_t n) const;character (4) size_t find_last_of (char c, size_t pos npos) const;
1.size_t find_last_of(const string str, size_t pos npos) const
从pos位置开始逆向查找首个与对象str中任一字符匹配的字符查找失败返回npos
2.size_t find_last_of(const char* s, size_t pos npos) const
ni从pos位置开始逆向查找首个与字符串s中任意字符匹配的字符查找失败返回npos
3.size_t find_last_of(const char* s,size_t pos, size_t n) const
从pos位置开始逆向查找首个与字符串s的前n个字符中任意字符匹配的字符查找失败返回npos
4.size_t find_last_of(char c, size_t pos npos) const
ni从pos位置开始逆向查找首个与字符c匹配的字符查找失败返回npos
void SplitFilename(const string str)
{size_t found str.find_last_of(/\\);cout path : str.substr(0, found) endl;cout file : str.substr(found 1) endl;
}
void string_test()
{string s1(/usr/bin/man);string s2(c:\\windows\\winhelp.exe);SplitFilename(s1);SplitFilename(s2);}
int main()
{string_test();//path: / usr / bin//file : man//path : c:\windows//file : winhelp.exereturn 0;
} 8.find_first_not_of() 正向查找不匹配的字符
正向查找首个与指定字符串中任一字符不匹配的字符查找失败返回npos
string (1) size_t find_first_not_of (const string str, size_t pos 0) const;c-string (2) size_t find_first_not_of (const char* s, size_t pos 0) const;buffer (3) size_t find_first_not_of (const char* s, size_t pos, size_t n) const;character (4) size_t find_first_not_of (char c, size_t pos 0) const;
1.size_t find_first_not_of(const string str, size_t pos 0) const
从pos位置开始正向查找首个与对象str中字符不匹配的字符查找失败返回npos
2.size_t find_first_not_of(const char* s, size_t pos 0) const
从pos位置开始正向查找首个与字符串s中字符不匹配的字符查找失败返回npos
3.size_t find_first_not_of(const char* s, size_t pos, size_t n) const
从pos位置开始正向查找首个与字符串s前n个字符中字符不匹配的字符查找失败返回npos
4.size_t find_first_not_of(char c, size_t pos 0) const
从pos位置开始正向查找首个与字符c不匹配的字符查找失败返回npos
string str(look for non-alphabetic characters...);
size_t found str.find_first_not_of(abcdefghijklmnopqrstuvwxyz );
if (found ! string::npos)
{cout The first non-alphabetic character is str[found] at position found endl;//The first non-alphabetic character is - at position 12
}
9.find_last_not_of() 逆向查找不匹配的字符 逆向查找首个与指定字符串中任一字符不匹配的字符查找失败返回npos
string (1) size_t find_last_not_of (const string str, size_t pos npos) const;c-string (2) size_t find_last_not_of (const char* s, size_t pos npos) const;buffer (3) size_t find_last_not_of (const char* s, size_t pos, size_t n) const;character (4) size_t find_last_not_of (char c, size_t pos npos) const;
1.size_t find_last_not_of(const string str, size_t pos npos) const
从pos位置开始逆向查找首个与对象str中字符不匹配的字符查找失败返回npos
2.size_t find_last_not_of(const char* s, size_t pos npos) const
从pos位置开始逆向查找首个与字符串s中字符不匹配的字符查找失败返回npos
3.size_t find_last_not_of(const char* s, size_t pos, size_t n) const
从pos位置开始逆向查找首个与字符串s前n个字符中字符不匹配的字符查找失败返回npos
4.size_t find_last_not_of(char c, size_t pos npos) const
从pos位置开始逆向查找首个与字符c不匹配的字符查找失败返回npos
string str(Please, erase trailing white-spaces \n);
string whitespaces( \t\f\v\n\r);
size_t found str.find_last_not_of(whitespaces);
if (found ! string::npos)str.erase(found 1); //[Please, erase trailing white-spaces]
elsestr.clear();
cout [ str ] endl;
10.compare() 比较字符串
比较两个字符串的ASCII码值字符串1大于字符串2返回大于0的数字符串1等于字符串2返回0字符串1小于字符串2返回小于0的数
string (1) int compare (const string str) const;substrings (2) int compare (size_t pos, size_t len, const string str) const;
int compare (size_t pos, size_t len, const string str,size_t subpos, size_t sublen) const;c-string (3) int compare (const char* s) const;
int compare (size_t pos, size_t len, const char* s) const;buffer (4) int compare (size_t pos, size_t len, const char* s, size_t n) const;
1.int compare(const string str) const
比较调用对象和str对象的大小
2.int compare(size_t pos, size_t len, const string str) const
比较调用对象pos位置开始的len个字符与对象str的大小
int compare(size_t pos, size_t len, const string str, size_t subpos, size_t sublen) const
比较调用对象pos位置开始的len个字符与对象str中subpos位置开始的sublen个字符的大小
3.int compare(const char* s) const
比较调用对象和字符串s的大小
int compare(size_t pos, size_t len, const char* s) const
比较调用对象从pos位置开始的len个字符与字符串s的大小
4.int compare(size_t pos, size_t len, const char* s, size_t n) const
比较调用对象从pos位置开始的len个字符与字符串s前n个字符的大小
//1.
string s1(abcdefg);
string s2(abcdfg);
if (s1.compare(s2) 0)cout s1 s2 endl;
else if (s1.compare(s2) 0)cout s1 s2 endl;
elsecout s1 s2 endl; //abcdefg abcdfg//2.1
string s1(abcdefg);
string s2(abcdfg);
if (s1.compare(1, 6, s2) 0)cout s1 s2 endl;
else if (s1.compare(1, 6, s2) 0)cout s1 s2 endl;//abcdefg abcdfg
elsecout s1 s2 endl; //2.2
string s1(abcdefg);
string s2(abcdfg);
if (s1.compare(1, 6, s2, 1, 5) 0)cout s1 s2 endl;
else if (s1.compare(1, 6, s2, 1, 5) 0)cout s1 s2 endl;
elsecout s1 s2 endl;//abcdefg abcdfg//3.1
string s(abcdefg);
char p[] abcdfg;
if (s.compare(p) 0)cout s p endl;
else if (s.compare(p) 0)cout s p endl;
elsecout s p endl;//abcdefg abcdfg//3.2
string s(abcdefg);
char p[] abcdfg;
if (s.compare(1, 5, p) 0)cout s p endl;
else if (s.compare(1, 5, p) 0)cout s p endl;//abcdefg abcdfg
elsecout s p endl;//4
string s(abcdefg);
char p[] abcdfg;
if (s.compare(1, 5, p, 5) 0)cout s p endl;
else if (s.compare(1, 5, p, 5) 0)cout s p endl;//abcdefg abcdfg
elsecout s p endl;
