我正在尝试使用"按' q'退出"退出do ... while循环的功能,用于计算一系列用户定义的整数的平均值。在几个例子之后,我能够使退出值起作用,但它被包含在计算平均值的一部分中。
示例:
quixote@willow:~$ gcc sentinel-borked.c -o sentinel-borked
sentinel-borked.c: In function 'main':
sentinel-borked.c:22:13: warning: assignment makes integer from pointer without a cast [-Wint-conversion]
sum = sum + value;
^
quixote@willow:~$ ./sentinel-borked
Enter an answer string or q to quit: 1
Enter an answer string or q to quit: 1
Enter an answer string or q to quit: q
Count is: 3
Average is: 214197589.333333
quixote@willow:~$
我知道" q"被视为整数,但我不确定如何重写我的代码以逃避它。 :(
我能想到的最简单的解决方法是提示用户提供一个终点(即"你平均有多少个整数?")并使用它,但我真的想知道这个进行。
这是我到目前为止的代码。
#include <stdio.h>
#include <string.h>
int main ()
{
/* variable definition: */
int count, sum;
double avg;
char *value;
/* Initialize */
count = 0;
sum = 0;
avg = 0.0;
do {
// Loop through to input values
printf("\nEnter an answer string or q to quit: ");
fgets(value, 10, stdin);
if (value >= 0){
sum = sum + value;
count = count + 1;
}
else {
printf("\nValue must be positive");
}
} while (value[0] != 'q');
// Calculate avg. Need to type cast since two integers will yield an integer
printf("\nCount is: %d", count);
avg = (double) sum/count;
printf("\nAverage is: %lf\n", avg);
return 0;
}
编辑:用代码块内的纯文本替换了屏幕截图。原始图片仍位于:https://i.stack.imgur.com/qza1N.png
答案 0 :(得分:1)
试试这个:
#include <stdio.h>
#include <string.h>
int main ()
{
/* variable definition: */
int count, sum;
double avg=0;
char value[10]="";//make value an array or allocate memory for it using malloc and also null initiate it
/* Initialize */
count = 0;
sum = 0;
avg = 0.0;
fgets(value,10,stdin);
if(value[strlen(value)-1]=='\n'){//if the user enters a string less than 10 chars a newline will also be stored inside the value array
value[strlen(value)-1]='\0';//you need to remove that \n and replace it with null
}
else{
while((getchar())!='\n');//just removing any extra chars left(when the user enters a string greater than 10 chars)
}
while(value[0]!='q'){//beware it will only check for the first char of the array to be q, anything else will still proceed the loop
sum+=strtol(value,NULL,10);//use this to convert integers inside the array to long ints(many other ways exists)
count++;
fgets(value,10,stdin);//overwrite value each time to get input
if(value[strlen(value)-1]=='\n'){
value[strlen(value)-1]='\0';
}
else{
while((getchar())!='\n');
}
}
// Calculate avg. Need to type cast since two integers will yield an integer
printf("\nCount is: %d", count);
if(count==0){
printf("\nAverage is: %lf\n", avg);
}
else{
avg = (double) sum/count;
printf("\nAverage is: %lf\n", avg);
}
return 0;
}