[Leetcode series] string to INTEGER (atoi)

Then I went directly to the Code. At first I counted "ABC123" as legal. Later I checked the definition of atoi and removed it.

Public class solution {public static int atoi (string instr) {long result = 0l;/** check it online. The definition of atoi function is that if the first non-space character exists, if it is a number or plus or minus sign, type conversion starts. * If it detects a non-digit (including the terminator \ 0) character, the conversion is stopped and the integer number is returned. Otherwise, zero is returned. Possible inputs include: 1. Empty strings * 2, "123abc", "1a2b3c", "ABC123", "-123abc" 3. Overflow 4. Spaces * // Step 1: filter space instr = instr. trim (); char [] inchararray = instr. tochararray (); int Index = 0; // step2: Positive and Negative char flag = '+ '; if (inchararray [0] = '+' | inchararray [0] = '-') {flag = inchararray [0]; Index = 1;} // Step 3: conversion and various judgments for (INT I = index; I <inchararray. length; I ++) {If (character. isdigit (inchararray [I]) {result = Result * 10 + integer. parseint (inchararray [I] + "") ;}else {break ;}// step4: If (flag = '-') {result =-result;} // step5: whether to overflow if (result> integer. max_value) {result = integer. max_value;} else if (result <integer. min_value) {result = integer. min_value;} return (INT) result;} public static void main (string [] ARGs) {// system. out. println (integer. max_value + "" + integer. min_value); string [] testcase = {"123abc", "+ 123abc", "-123abc", "123abc", "ABC123", "1ab2c3", "2222222222 ", "-2222222222"}; For (string test: testcase) {system. out. print (atoi (TEST); system. out. println ();}}}