C++ Program to Convert String to Integer
Given a string of digits, the task is to convert the string to an integer. Examples:
Input : str = "12345" Output : 12345 Input : str = "876538"; Output : 876538 Input : str = "0028"; Output : 28
CPP
// C++ program to convert String into Integer #include <bits/stdc++.h> using namespace std; // function for converting string to integer int stringTointeger(string str) { int temp = 0; for ( int i = 0; i < str.length(); i++) { // Since ASCII value of character from '0' // to '9' are contiguous. So if we subtract // '0' from ASCII value of a digit, we get // the integer value of the digit. temp = temp * 10 + (str[i] - '0' ); } return temp; } // Driver code int main() { string str = "12345" ; int num = stringTointeger(str); cout << num; return 0; } |
Output:
12345
Time Complexity: O(|str|)
Auxiliary Space: O(1)
How to do using library functions? Please refer Converting Strings to Numbers in C/C++ for library methods.