方法一：
给你的登录函数（ logon）添加一个返回值，登录成功返回1，失败返回0。
在main函数case里调用logon时，验证返回值。
方法二：
在三次密码错误后（printf("三次均错误，退出程序\n")这句后面），用exit函数直接结束程序（头文件stdlib.h）。
//小游戏：猜数字 随机一个1-100之间的数，根据数据输入进行提示#include <stdlib.h>
#include <time.h>
int main(void){
int value=0
int num=0
srand((unsigned int) time(NULL))
num=rand()%100+1//1-100
while(1){
scanf("%d",&value)
if(num>value){
printf("您猜小了\n")
}
else if(num<value){
printf("您猜大了\n")
}
else if(num=value){
printf("恭喜您猜对了\n")
break
}
}
return 0
}
小游戏2048：
#include<stdio.h>
#include<stdlib.h>
#include<conio.h>
#include<time.h>
#include<windows.h>
int jsk( ) //计算空格数
void rsgm( ) //重置游戏
void inkey( ) //按键输入
void left( ) //向左移动
void right( ) //向右移动
void up( ) //向上移动
void down( ) //向下移动
void show( ) //输出界面
void adnum( )//添加随机数
void yes( ) //游戏是否结束(1是0否)
void gtxy(int x, int y)//控制光标位置的函数
int a[4][4] //存储16个格子中的数字
int score = 0 //每局得分
int best = 0 //最高得分
int ifnum //是否需要添加数字(1是0否)
int over //游戏结束标志(1是0否)
int i,j,k
int main( )
{ rsgm( ) //重置游戏
inkey( ) //按键输入
return 0
}
void Color(int a) //设定字符颜色的函数(a应为1-15)
{ SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE),a) }
void rsgm( ) //重置游戏
{ score = 0ifnum = 1over = 0srand((unsigned)time(0)) //启动随机数发生器
int n = rand( ) % 16 //随机函数产生0-15的数字
for (i = 0i <4i++)
{for (j = 0j <4j++)
{ if (n == 0) { int k = rand( ) % 3if (k == 0 || k == 1) { a[i][j] = 2}
else { a[i][j] = 4} n--}
else { a[i][j] = 0n--}
}
}
adnum( )
system("cls")
CONSOLE_CURSOR_INFO gb={1,0} //以下两行是隐藏光标的设置,gb代指光标
SetConsoleCursorInfo( GetStdHandle(STD_OUTPUT_HANDLE), &gb )
Color(14) //设置字体淡黄色
printf("\n\n\t\t 2048小游戏")Color(7) //恢复白字黑底
printf("\n\t┌──────┬──────┬──────┬──────┐")
printf("\n\t│ │ │ │ │")
printf("\n\t├──────┼──────┼──────┼──────┤")
printf("\n\t│ │ │ │ │")
printf("\n\t├──────┼──────┼──────┼──────┤")
printf("\n\t│ │ │ │ │")
printf("\n\t├──────┼──────┼──────┼──────┤")
printf("\n\t│ │ │ │ │")
printf("\n\t└──────┴──────┴──────┴──────┘")
show( )
}
void show( ) //输出界面
{ for(i=0i<4i++)
for(j=0j<4j++)
{ gtxy(7*j+9,2*i+4) //gtxy(7*j+9, 2*i+4)是光标到指定位置输出数字
if(a[i][j]==0){printf(" ")Color(7)printf("│")}
else if(a[i][j]<10){ if (a[i][j] == 2) { Color(14)}
else if (a[i][j] == 4) { Color(13)}
else if (a[i][j] == 8) { Color(12)}
printf(" %d ", a[i][j])Color(7 )printf("│")
}
else if (a[i][j] <100){if (a[i][j] == 16) { Color(12)}
else if (a[i][j] == 32) { Color(10)}
else if (a[i][j] == 64) { Color(2 )}
printf(" %d ", a[i][j])Color(7)printf("│")
}
else if (a[i][j] <1000) {if (a[i][j] == 128) { Color(9)}
else if (a[i][j] == 256) { Color(1)}
else if (a[i][j] == 512) { Color(13)}
printf(" %d ", a[i][j])Color(7)printf("│")
}
else if (a[i][j] <10000) {if (a[i][j] == 1024) { Color(5)}
else { Color(15)}
printf(" %d ", a[i][j])Color(7)printf("│")
}
}
if (jsk( ) == 0)
{ yes( ) if (over) { gtxy(9,12)Color(10)
printf("\n\n 游戏结束！是否继续? [ Y/N ]:")}
}
}
void inkey( ) //按键输入
{ int key
while (1)
{ key = getch( )
if (over) { if (key == 89|| key == 121) { rsgm( )continue}
else if (key == 78|| key == 110) { return}
else continue}
ifnum = 0
if(key==224)key=getch( )
switch (key)
{ case 75: left( )break
case 77: right( )break
case 72: up( )break
case 80: down( )break
}
if (score >best) { best = score}
if (ifnum) { adnum( )show( )}
}
}
int jsk( ) //计算空格数
{ int n = 0
for (i = 0i <4i++)
{ for (j = 0j <4j++) { if ( a[i][j] == 0) {n++} } }
return n
}
void left( ) //向左移动
{ for (i = 0i <4i++)
{for (j = 1, k = 0j <4j++)
{ if (a[i][j] >0)
{ if ( a[i][k] == a[i][j])
{ a[i][k] *= 2 k++
score = score + 2 * a[i][j]
a[i][j] = 0 ifnum = 1}
else if ( a[i][k] == 0) { a[i][k] = a[i][j]a[i][j] = 0ifnum = 1}
else { a[i][k + 1] = a[i][j]if ((k + 1) != j) { a[i][j] = 0ifnum = 1}
k++}
}
}
}
}
void right( ) //向右移动
{for (i = 0i <4i++)
{for (j = 2, k = 3j >= 0j--)
{if (a[i][j] >0)
{ if (a[i][k] == a[i][j])
{a[i][k] *= 2k--score = score + 2 * a[i][j]a[i][j] = 0ifnum = 1}
else if ( a[i][k] == 0) {a[i][k] = a[i][j]a[i][j] = 0ifnum = 1}
else { a[i][k - 1] = a[i][j]if ((k - 1) != j) { a[i][j] = 0ifnum = 1} k--}
}
}
}
}
void up( ) //向上移动
{for (i = 0i <4i++)
{for (j = 1, k = 0j <4j++)
{if (a[j][i] >0)
{if ( a[k][i] == a[j][i]) { a[k][i] *= 2k++score = score + 2 * a[j][i]
a[j][i] = 0ifnum = 1}
else if ( a[k][i] == 0) { a[k][i] = a[j][i]a[j][i] = 0ifnum = 1}
else { a[k + 1][i] = a[j][i]if ((k + 1) != j) { a[j][i] = 0ifnum = 1}
k++}
}
}
}
}
void down( ) //向下移动
{ for (i = 0i <4i++)
{for (j = 2, k = 3j >= 0j--)
{if (a[j][i] >0)
{if (a[k][i] == a[j][i])
{a[k][i] *= 2k--score = score + 2 * a[j][i]a[j][i] = 0ifnum = 1}
else if (a[k][i] == 0) {a[k][i] = a[j][i]a[j][i] = 0ifnum = 1}
else {a[k - 1][i] = a[j][i]
if ((k - 1) != j) {a[j][i] = 0ifnum = 1} k--}
}
}
}
}
void adnum( ) //添加随机数
{ srand(time(0))int n = rand( ) % jsk( )
for (int i = 0i <4i++)
{for (int j = 0j <4j++)
{ if (a[i][j] == 0) {if (n != 0) { n--}
else {int k = rand( ) % 3
if (k == 0 || k == 1) {a[i][j] = 2return}
else {a[i][j] = 4return} }
}
}
}
}
void yes( ) //游戏是否结束
{ for (int i = 0i <4i++)
{for (int j = 0j <3j++)
{if (a[i][j] == a[i][j + 1] || a[j][i] == a[j + 1][i]) {over = 0return}}
}
over = 1
}
void gtxy(int x, int y) //控制光标位置的函数
{ COORD zb //zb代指坐标
zb.X = x
zb.Y = y
SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE), zb)
}
