题目:输入abc123，输出abc.

指针

void del_digit(char *str) {
    char *ep = str;
    char *sp = str;
    while (*sp) {
        if (isdigit(*sp)) {
            sp++;
        } else {
            *ep++ = *sp++;
        }
    }
    *ep = '\0';
}

循环

void del_digit2(char str[]) {
    int i = 0;
    int j = 0;
    while (str[i]) {
        if (isdigit(str[i])) {
            i++;
        } else {
            str[j++] = str[i++];
        }
    }
    str[j] = '\0';
}

测试:

    char del[128];
    printf("输入删除的字符:");
    scanf("%s",del);
    del_digit(del);
    printf("FlyElephant:删除之后的结果:%s\n",del);
    
    char del2[128];
    printf("输入删除的字符2:");
    scanf("%s",del2);
    del_digit2(del2);
    printf("FlyElephant:删除之后的结果2:%s\n",del2);

测试结果.png