将int转化为string的问题，附加条件是字符数组有最小宽度，不够就以空格补齐
程序代码：#include <stdio.h>
#include <string.h>
void reverse(char s[])
{int i,j;
char c;
for(i=0,j=strlen(s)-1;i<j;i++,j++)
{c=s[i];s[i]=s[j];s[j]=c;}
}
void itoa(int n,char s[],int w)
{int i=0,sign;
if((sign=n)<0)n=-n;
do
{s[i++]=n%10;}while(n/=10>0);
if(sign<0)s[i]='-';
if(i<w)
for(;i<=w;i++)
s[i]=' ';
s[i]='\0';
reverse(s);
}
int main(void)
{int n=994,w=5;
char s[100];
itoa(n,s,w);
printf(s);
}//where is the problem?
