在c语言中创建while循环

Question

我刚刚开始学习C，我决定创建一个while循环来确保我掌握了一些东西。这是我的代码:

#include <stdio.h>
void main(){
int num, guess, turns;
num = 13;
guess = getchar();
turns = 0;

while(guess != num){
printf("%d", guess);
++turns;
printf("Turns:n");
printf("%d", turns);
guess;
}      
}

它给了我一个无限循环。谁能告诉我我哪里做错了?另外，如果你有任何建议或提示，请随时留下。

Answer 1

getchar()不能从终端读取，必须使用:

scanf(" %d", &guess);

在while循环中，你必须再次从终端读取值(如果猜错了)

while(guess != num){
printf("Turns:n");
printf("%d", guess);
++Turns;
scanf(" %d", &guess);
}
printf("%d is the correct guess", guess);

Answer 2

我在你的代码中发现了两个问题首先是你在使用"getchar"而不是"scanf"当尝试获取整数输入时。

第二个问题是你没有更新"guess"的值在while循环内(这会导致无限循环)

为了您的方便下面是代码

的固定版本

void main() {
printf("start n");
int num, guess, turns;
num = 13;

scanf("%d", &guess);
turns = 0;

while(guess != num){
printf("your guess was : %d n", guess);
++turns;
printf("Turns:");
printf("%d n", turns);

scanf("%d", &guess);
}      

}

希望我能帮上忙:)

Answer 3

在while循环中，变量guess未被更改

while(guess != num){
printf("%d", guess);
++turns;
printf("Turns:n");
printf("%d", turns);
guess;
}  

而且这一行

guess;

不起作用

while循环前的语句

guess = getchar();

没有意义，因为函数getchar只读取一个字符并返回该字符的内部表示的值。

还需要注意的是，根据C标准，不带参数的main函数应该像

这样声明。

int main( void )

你的程序可以像下面这样

#include <stdio.h>
int main( void )
{
unsigned int num = 13;
unsigned int turns = 0;

unsigned int guess = 0;
puts( "Try to guess the number I thought." );
printf( "Enter a non-negative number: " );
while( scanf( "%u", &guess ) == 1 && guess != num )
{
printf( "%u is not my number.n", guess );
++turns; 
printf( "It is your %u attemptn", turns );
printf( "nEnter a non-negative number: " );
}
if ( guess == num )
{
printf( "nYou have guessed the number using %u guesses.n", turns );
}
else
{
printf( "nYou have not guessed the number using &u guesses.n", turns );
}
}