自己写个字符串转int(my_atoi)

#include "stdio.h"int isDigit(int s)//判断是否是数字{if(s >= '0' && s <= '9')return 1;elsereturn 0;}int my_atoi(const char* str){int c;int sum = 0;int sign;while((*str)==' ' || (*str) == '\n' || (*str) == '\r' || (*str) == '\t')//判断是否是空格换行之类的空字符，有则跳过str++;sign = *str; //符号if(sign == '-' || sign == '+')//若有符号则跳过str++;c = (int)*str++;while(isDigit(c)){sum = 10 * sum + (c - '0');c = (int)*str++;}if(sign == '-')return -sum;elsereturn sum;}int main(){char* str = "-123";printf("%d\n",my_atoi(str));return 0;}