字符串初始化
void main() {
string s1 = "111111";
string s2("22222");
string s3 = s2;
cout << s1<< endl;
cout << s2 << endl;
cout << s3 << endl;
}
字符串遍历
使用[]和使用at()遍历的差别在于，at()发生数组越界会抛出异常，可以捕获，但是[]方式发生异常无法进行捕获
//通过角标取值
void main() {
string s1 = "abcdefg";
for (int i = 0; i < s1.length(); i++){
cout << s1[i];
}
}
//通过at()取值
void main() {
string s1 = "abcdefg";
for (int i = 0; i < s1.length(); i++){
cout << s1.at(i);
}
}
//使用迭代器遍历
void main() {
string s1 = "abcdefg";
for (string::iterator i = s1.begin(); i != s1.end(); i++) {
//迭代器可以看作指针
cout << *i<< endl;
}
}
string char的转换
void main(){
string s1 = "aaabbbccc";
// to char
cout << s1.c_str()<<endl;
char buf[128] = {0};
s1.copy(buf, 9, 0);
cout <<"buf="<< buf<< endl;
}
string链接
void main() {
string s2 = "aaa";
string s3 = "bbb";
s2 = s2 + s3;
cout << "s2 = "<<s2<< endl;
string s4 = "222";
string s5 = "444";
s4.append(s5);
cout << "s4="<<s4<< endl;
}
查找和替换
void main() {
string s = "who are you and who is she and who am i";
//从0开始查找
int index = s.find("who", 0);
while (index != string::npos) {
cout << "index="<<index << endl;
//替换,从0开始，替换三个字符
s.replace(index, 3, "WHOSE");
index = index + 1;
index = s.find("who", index);
}
cout << "替换后："<<s << endl;
}
删除字符
//找到指定字符，然后删除
void main() {
string s1 = "hello1 hello2 hello3";
string ::iterator it = find(s1.begin(), s1.end(), '1');
if (it != s1.end()) {
s1.erase(it);
}
cout << "删除之后："<<s1<< endl;
system("pause");
}
//删除指定范围的字符
void main() {
string s1 = "hello1hello2hello3";
s1.erase(1, 5);
cout << "删除1到5位置的字符后：" << s1 << endl;
system("pause");
}
插入字符
void main() {
string s1 = "how are you today";
s1.insert(0, "hello ");
cout << "插入后：" << s1 << endl;
system("pause");
}
大小写转换
void main() {
string s1 = "how are you today";
transform(s1.begin(), s1.end(), s1.begin(), toupper);
cout << "转换后：" << s1 << endl;
string s2 = "I AM GOOD";
transform(s2.begin(), s2.end(), s2.begin(), tolower);
cout << "转换后：" << s2 << endl;
system("pause");
}
