Your task is to implement the function atoi. The function takes a string(str) as argument and converts it to an integer and returns it.
str = 123
str = 21a
Explanation: Output is -1 as all
characters are not digit only.
Complete the function atoi() which takes a string as input parameter and returns integer value of it. if the input string is not a numerical string then returns 1..
Expected Time Complexity: O(|S|), |S| = length of string S. Expected Auxiliary Space: O(1)
1<=length of (s,x)<=10
Note:The Input/Ouput format and Example given are used for system's internal purpose, and should be used by a user for Expected Output only. As it is a function problem, hence a user should not read any input from stdin/console. The task is to complete the function specified, and not to write the full code.