C – 从int获取字符串

例如长度3

000
100
200
.
.
900
A00
B00
.
.
Z00
a00
b00
.
.
z00
010
.
.
.
zzz

我试图写valueof(int pos,int len)接受一个位置int作为参数并在该位置打印String(例如,valueof(1,3)打印000和valueof(109,3)打印k10

这是我尝试过的,它不起作用：

void valueof(int pos,int len)
{   

    int i=0;
    char arrY[62] = {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
    char * String = malloc(sizeof(char)*(len+1));
    for(i=0; i<len; i++)
    {
        String[i]='0';
    }
    String[len]='\0';
    i=0;
    while(pos >= 62)
    {
        String[i]=arrY[(pos%62)-1];
        i++;
        pos/=62;
    }
    String[i]=arrY[pos];

    printf("%s\n",String);
}