Implementing the Atoi function

The key point of the Atoi function is to think about the test case:

• The input is an empty string and the output is 0;
• The input string size exceeds Int_max output int_max;
• The input string size is less than int_min output int_min;
• The input string contains irregular characters and interrupts atoi, such as "01a4" Output 1;
• The input string begins and ends with spaces, ignoring spaces, such as input "+01" Output 1;
• The input string begins with "+" and "-", except for spaces, as entered correctly.

classSolution { Public:    intAtoiConst Char*str) {        if(strlen (str) = =0)return 0; Doubleresult=0; intj=0;  while(str[j]==' ')//Ignore string first space{J++; }        intlast = strlen (str)-1; intLast_space =0;  while(str[last]==' ')//Ignore string trailing spaces{ Last--; Last_space++; }        if(str[j]=='+')        {             for(inti=j+1; I<strlen (str)-last_space;i++)            {                if(str[i]>='0'&&str[i]<='9') {result= result*Ten+ (str[i]-'0'); }                //terminating conversion If illegal characters are encountered                Else                {                     Break; }            }            if(result>Int_max) {                returnInt_max; }            Else            {                returnresult; }        }        if(str[j]=='-')        {             for(inti=j+1; I<strlen (str)-last_space;i++)            {                if(str[i]>='0'&&str[i]<='9') {result= result*Ten+ (str[i]-'0'); }                Else                {                     Break; }            }            if(Result* (-1) <int_min) {                returnint_min; }            returnresult* (-1); }         for(intI=j;i<strlen (str)-last_space;i++)        {            if(str[i]>='0'&&str[i]<='9') {result= result*Ten+ (str[i]-'0'); }            Else            {                 Break; }        }        if(result>Int_max) {            returnInt_max; }        if(Result* (-1) <int_min) {            returnint_min; }        returnresult; }};

Implementing the Atoi function