c语言-c语言编程基础之leetcode题解第8题字符串转整数.zip

#include <ctype.h> #include <stdio.h> #include <stdlib.h> #include <limits.h> static int myAtoi(char* str) { char *s; long n = 0; int sign = 0; while (*str == ' ' || *str == '\t') { str++; } if (*str == '-') { if (isdigit(*++str)) { sign = 1; } else { return 0; } } if (*str == '+') { if (isdigit(*++str)) { sign = 0; } else { return 0; } } for (s = str; *s != '\0'; s++) { if (isdigit(*s)) { int d = *s - '0'; if (sign) { if (-n < (INT_MIN + d) / 10) { n = INT_MIN; break; } } else { if (n > (INT_MAX - d) / 10) { n = INT_MAX; break; } } n = n * 10 + d; } else { break; } } return sign ? -n : n; } int main(int argc, char **argv) { if (argc != 2) { printf("Usage: ./atoi 123\n"); exit(-1); } int n = myAtoi(argv[1]); printf("n = %d %x\n", n, n); return 0; }