std::stoul and std::stoull in C++
std::stoul
Convert string to unsigned integer. Parses str interpreting its content as an integral number of the specified base, which is returned as an unsigned long value.
unsigned long stoul (const string& str, size_t* idx = 0, int base = 10); Parameters : str : String object with the representation of an integral number. idx : Pointer to an object of type size_t, whose value is set by the function to position of the next character in str after the numerical value. This parameter can also be a null pointer, in which case it is not used. base : Numerical base (radix) that determines the valid characters and their interpretation. If this is 0, the base used is determined by the format in the sequence.Notice that by default this argument is 10, not 0.
std::stoull
Convert string to unsigned long long. Parses str interpreting its content as an integral number of the specified base, which is returned as a value of type unsigned long long.
unsigned long long stoull (const string& str, size_t* idx = 0, int base = 10); Parameters : str : String object with the representation of an integral number. idx : Pointer to an object of type size_t, whose value is set by the function to position of the next character in str after the numerical value. This parameter can also be a null pointer, in which case it is not used. base : Numerical base (radix) that determines the valid characters and their interpretation. If this is 0, the base used is determined by the format in the sequence. Notice that by default this argument is 10, not 0.
Examples:
Input : FF Output : 255 Input : FFFFF Output :
// CPP code to convert hexadecimal // string to int #include <bits/stdc++.h> using namespace std; int main() { // Hexadecimal string string str = "FF" ; // Converted integer unsigned long num = stoul(str, nullptr, 16); // Printing the integer cout << num << "\n" ; // Hexadecimal string string st = "FFFFFF" ; // Converted long long unsigned long long val = stoull(st, nullptr, 16); // Printing the long long cout << val; return 0; } |
Output:
255 16777215
Another Example : Program to compare two strings containing hexadecimal values
Here stoul is used, but in cases of numbers exceeding unsigned long value, stoull is used.
// CPP code to compare two // hexadecimal string #include <bits/stdc++.h> using namespace std; int main() { // Hexadecimal string string s1 = "4F" ; string s2 = "A0" ; // Converted integer unsigned long n1 = stoul(s1, nullptr, 16); unsigned long n2 = stoul(s2, nullptr, 16); // Compare both string if (n1 > n2) cout << s1 << " is greater than " << s2; else if (n2 > n1) cout << s2 << " is greater than " << s1; else cout << "Both " << s1 << " and " << s2 << " are equal" ; return 0; } |
Output:
A0 is greater than 4F
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