C++中的字符转换 to_string、sto

南林yan2024-04-13 13:49

将数字转换为字符串

string to_string(int val);

string to_string(long val);

string to_string(long long val);

string to_string(unsigned val);

string to_string(unsigned long val);

string to_string(unsigned long long val);

string to_string(float val);

string to_string(double val);

string to_string(long double val);

cpp 复制代码

int i = 10086;
double d = 3.1415926;
string s1 = to_string(i);
string s2 = to_string(d);
cout << s1 << endl;//10086
cout << s2 << endl;//3.1415926

将字符串转换为数字

参数：

str是需要转换的字符串；idx是需要转换的起始位置；base是确定转换为多少进制数

int stoi(const string & str, size_t * idx = 0, int base = 10);

long stol(const string & str, size_t * idx = 0, int base = 10);

unsigned long stoul(const string & str, size_t * idx = 0, int base = 10);

long long stoll(const string & str, size_t * idx = 0, int base = 10);

unsigned long long stoull(const string & str, size_t * idx = 0, int base = 10);

float stof(const string & str, size_t * idx = 0);

double stod(const string & str, size_t * idx = 0);

long double stold(const string & str, size_t * idx = 0);

cpp 复制代码

string s1("10086");
int i = stoi(s1);
cout << i << endl;//10086

string s2("3.1415926");
double d = stod(s2);
cout << s2 << endl;//3.1415926