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.
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