#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<math.h>
#include<time.h>
int main0101()
{
char ch[] = " -123-456";
//atoi会扫描字符串，跳过前面的空格字符，直到遇到数字或正负号才开始转换，而遇到非数字或字符串结束符 才结束
int i=atoi(ch);
printf("%d ", i);//-123
return EXIT_SUCCESS;
}
int main0102(void)
{
char ch[] = " -123.456-456abc123";
double i = atof(ch);
printf("%.2f ", i);//-123.56
return 0;
}
int main(void)
{
char ch[] = " -123.456-456abc123";
long i = atol(ch);
printf("%ld ", i);//-123
return 0;
}