/***************************************************************************
函数void dele(char *s)的功能是删除字符串s中的所有数字字符和非数字字符，并将
字符串压缩。例如原字符串为：abc12ef5ghij8#%%yz，处理后的字符串为:abcefghijyz.
****************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void dele(char *s)
{
    int lena,lenb,i,j;
    char b[200];

    i = 0;j = 0;
    while(s[i] != '\0')
    {
        if(s[i] >= 'a' && s[i] <= 'z')
        {
            b[j] = s[i];
            j++;i++;
        }
        else
            i++;
    }
    b[j] = '\0';


    lena = strlen(b);
    for(i = 0,j = 0;i < lena || j <lena;i++,j++)
    {
        s[i] = b[j];
    }
    s[i] = '\0';
}

int main(void)
{
    char s[200];

    printf("please input the string s:");
    gets(s);

    dele(s);

    puts(s);
    return 0;
}

for(i = 0,j = 0;j <=lena;i++,j++)
    {
        s[i] = b[j];
    }