程序代码：

void fun(int b){
    if(b>9){
        fun(b/10);
    }
    int c = b%10;
    if(c==0)
        printf("0");
    else{
        printf("%c",c+'A'-1);
    }
}
int main(){
    int a,temp;
    scanf("%d",&a);
    if(a<=26){
        printf("%c",a+'A'-1);
    }
    temp = (a/26)*10+a%26;
    fun(temp);
    printf("\n");
    return 0;
}

程序代码：

#include <stdio.h>
int base[26] = {'Z','A','B','C','D','E','F','G','H','I','J',//1-10
'K','L','M','N','O','P','Q','R','S','T',//11-20
'U','V','W','X','Y'};//21-26
int main()
{
    int i,j;
    int n;
    while(EOF != scanf("%d",&n))
    {
        int k = 0;
        int bit[100] = {0};
        while(n)
        {
            bit[k++] = n%26;
            n /= 26;
        }
        while(k--)
        {
            putchar(base[bit[k]]);
        }
        printf("\n");
    }
    return 0;
}