分析：
str数组接受不规范的电话字符串，number数组储存标准化的电话号码，qsort(stdlib库函数)将number数组排序，通过检测排序后的number数组得知同一个号码的重复次数，
compare函数用于qsort函数的实现（类似于实现接口）
strandradStr函数用于是电话号码的标准化
源码：
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
char str[20];
char number[10000][9];
//char* elem1 char* elem2
int compare(const void *elem1, const void *elem2)
{
return(strcmp((char*)elem1, (char*)elem2));
}
void strandradStr(int i)
{
bool flag = false;
int j;
for(j = 0; str[j] != ‘\0‘; j++)
{
if(str[j] == ‘-‘)
flag = true;
if(str[j]==‘A‘ || str[j]==‘B‘ || str[j]==‘C‘)
str[j] = ‘2‘;
else if(str[j]==‘D‘ || str[j]==‘E‘ || str[j]==‘F‘)
str[j] = ‘3‘;
else if(str[j]==‘G‘ || str[j]==‘H‘ || str[j]==‘I‘)
str[j] = ‘4‘;
else if(str[j]==‘J‘ || str[j]==‘K‘ || str[j]==‘L‘)
str[j] = ‘5‘;
else if(str[j]==‘M‘ || str[j]==‘N‘ || str[j]==‘O‘)
str[j] = ‘6‘;
else if(str[j]==‘P‘ || str[j]==‘R‘ || str[j]==‘S‘)
str[j] = ‘7‘;
else if(str[j]==‘T‘ || str[j]==‘U‘ || str[j]==‘V‘)
str[j] = ‘8‘;
else if(str[j]==‘W‘ || str[j]==‘X‘ || str[j]==‘Y‘)
str[j] = ‘9‘;
}
int k = 0;
for(j = 0; str[j] !=‘\0‘ && flag; j++)
{
if(str[j] != ‘-‘)
{
str[k] = str[j];
k++;
}
}
if(flag)
str[k] = ‘\0‘;
int m;
for(m = 0; str[m] != ‘\0‘; m++)
//printf("%s\n", str);
number[i][m] = str[m];
str[m] = ‘\0‘;
}
int main()
{
int n;
scanf("%d" , &n);
for(int i = 0; i < n; i++)
{
scanf("%s", str);
//将输入字符串格式化为数字
//保存在number[i][9]
strandradStr(i);
}
//number数组排序
qsort(number, n, 9, compare);
bool noduplicate = true;
int i = 0;
int j = 0;
while(i<n)
{
j = i;
i++;
while(i<n && strcmp(number[j],number[i]) == 0)i++;
if(i - j > 1)
{
printf("%s %d\n", number[j], i-j);
noduplicate = false;
}
}
if(noduplicate)
{
printf("No duplicates.\n");
}
return 0;
}