在C中遇到for循环问题，它不打印输出？ [英] Having problems with for loop in C, it doesn't print the output ?
问题描述
编写一个c程序来查找最大的n个数字。
输出不显示print语句。并且对使用break语句的位置感到困惑。
我尝试了什么：
To write a c program to find the biggest of n numbers.
The output doesn't show the print statement. And having confusion on where to use the break statement.
What I have tried:
#include <conio.h>
#include <stdio.h>
int main(){
int total[100];
int count = 0, i=0;
int num, j, k;
printf("Enter the number: \t");
scanf(" %d", &num);
while(num!=0){
total[i] = num%10;
count++; // for every number it increments i.e. it is the length of the num entered.
num /= 10 ;
i++;
}
/* printf(" %d \n", count);
for(j=0;j<=count-1; j++){
printf(" %d", total[j]);
}
*/
for(j=1; j<=count; j++){
for(k=1; k<=count; k++){
if(total[j] > total[k]){ /*for total[j] it will check if it is greater then all the
others or not */
printf(" %d is the greatest number", total[j]);
//break;
}
//break;
}
}
getch();
return 0;
}
推荐答案
编译并不意味着你的代码是对的！ ：笑：
将开发过程想象成编写电子邮件：成功编译意味着您使用正确的语言编写电子邮件 - 例如英语而不是德语 - 而不是电子邮件包含您的邮件想发送。
所以现在你进入第二阶段的发展（实际上它是第四或第五阶段，但你将在之后的阶段进入）：测试和调试。
首先查看它的作用，以及它与你想要的有何不同。这很重要，因为它可以为您提供有关其原因的信息。例如，如果程序旨在让用户输入一个数字并将其翻倍并打印答案，那么如果输入/输出是这样的：
Compiling does not mean your code is right! :laugh:
Think of the development process as writing an email: compiling successfully means that you wrote the email in the right language - English, rather than German for example - not that the email contained the message you wanted to send.
So now you enter the second stage of development (in reality it's the fourth or fifth, but you'll come to the earlier stages later): Testing and Debugging.
Start by looking at what it does do, and how that differs from what you wanted. This is important, because it give you information as to why it's doing it. For example, if a program is intended to let the user enter a number and it doubles it and prints the answer, then if the input / output was like this:
Input Expected output Actual output
1 2 1
2 4 4
3 6 9
4 8 16然后很明显问题出在将它加倍的位 - 它不会将自身加到自身上，或者将它乘以2，它会将它自身相乘并返回输入的平方。
所以，你可以查看代码和很明显，它在某处：
Then it's fairly obvious that the problem is with the bit which doubles it - it's not adding itself to itself, or multiplying it by 2, it's multiplying it by itself and returning the square of the input.
So with that, you can look at the code and it's obvious that it's somewhere here:
int Double(int value)
{
return value * value;
}
一旦你知道可能出现的问题，就开始使用teh调试器找出原因。在您的行上设置一个断点：
Once you have an idea what might be going wrong, start using teh debugger to find out why. Put a breakpoint on your line:
for(j=1; j<=count; j++){
并运行你的应用程序。在执行代码之前，请考虑代码中的每一行应该做什么，并将其与使用Step over按钮依次执行每一行时实际执行的操作进行比较。使用调试器查看变量包含的值。它符合您的期望吗？如果是这样，请转到下一行。
如果没有，为什么不呢？它有何不同？
这是一项非常值得开发的技能，因为它可以帮助你在现实世界和发展中。和所有技能一样，它只能通过使用来改进！
and run your app. Think about what each line in the code should do before you execute it, and compare that to what it actually did when you use the "Step over" button to execute each line in turn. Use the debugger to look at what values variables contain. Did it do what you expect? If so, move on to the next line.
If not, why not? How does it differ?
This is a skill, and it's one which is well worth developing as it helps you in the real world as well as in development. And like all skills, it only improves by use!
这不是打印，而是程序的逻辑。您应该使用变量来保存到目前为止找到的最大数量，并在检查完所有项目后打印：
It is not the printing but the logic of your program. Instead of printing every time when an item is greater than the other, you should use a variable to hold the maximum number found so far and print that after all items has been checked:
// Assume first number is max for now
int max = total[0];
for (j = 1; j < count; j++)
{
if (total[j] > max)
max = total[j];
}
printf(" %d is the greatest number\n", max);或者，如果您需要最大数字的索引：
Or if you need the index for the maximum number:
int max_index = 0;
for (j = 1; j < count; j++)
{
if (total[j] > total[max_index])
max_index = j;
}
printf(" %d is the greatest number\n", total[max_index]);
看起来你试图找出输入数字的最大数字。对于这样的任务，你既不需要数组也不需要for循环：只需提取它 - 即时：
It looks you are trying to find out the greatest digit of the input number. For such a task you don't need neither the array nor the for loops: just extract it -on-the-fly:
#include <stdio.h>
int main()
{
int num;
int greatest_digit = 0;
printf("Enter the number: \t");
scanf(" %d", &num);
while( num != 0 )
{
int digit = num % 10;
if (greatest_digit < digit) greatest_digit = digit;
num /= 10 ;
}
printf("the greatest digit is %d\n", greatest_digit);
getchar();
return 0;
}
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