程序代码：

#include<stdio.h>

int main(void)
{
    FILE *fp,*fp1;
    char str[200]={0},ch;
    int t = 0;
    printf("\t\t1：新建文件\n");
    printf("\t\t2：追加内容\n");
    printf("\t\t0：退出\n");
    printf("请选择：");
    scanf("%d",&t);
    switch(t)
    {
        case 1:
        {
            printf("请输入文件名：");
            gets(str);
            if( !(fp = fopen(str,"w") ) )
            {
                printf("新建失败！\n");
                return 0;
            }
        }break;
        case 2:
        {
            printf("请输入文件名：");
            gets(str);
            if( !(fp1 = fopen(str,"a+") ) )
            {
                printf("打开失败！\n");
                return 0;
            }
            while(ch != EOF)
            {
                ch = getchar();
                fputc(ch,fp1);
            }
        }break;
        case 0:
            return 0;
            break;
        default:
            printf("cw");
            break;
    }            
    fclose(fp);
    fclose(fp1);
    return 0;
}