#define _CRT_SECURE_NO_WARNINGS 
#include <stdio.h>
#include <stdlib.h>
#include<assert.h>

char *strrchr(char  *str,char ch)
{
    char *ret=NULL;
    assert(str);
    while(*str)
    {
        if (*str==ch)
            ret=str;
        str++;
    }
    return ret;
}

int main()
{
    char
 
 *string="hello my college";
    int ret=0;
    char ch=0;
    printf("please enter the ch:\n");
    scanf("%c",&ch);
    ret=(char)strrchr(string,ch);
    printf("%d\n",ret);
    system("pause");
    return 0;
}