[英]Converting a String to number and Back to String
I have a String for example "23:0"
which is a hour format.我有一个字符串,例如
"23:0"
,它是一个小时格式。 I need to convert this to a int so I can add time to it for example.例如,我需要将其转换为 int,以便我可以为其添加时间。 I have a string
"23:0"
I need to add 6 hours which would be "6:0"
which would then give me "5:0"
, and then convert this back to a string.我有一个字符串
"23:0"
我需要添加 6 个小时,这将是"6:0"
然后给我"5:0"
,然后将其转换回字符串。
Any ideas would be greatly appreciated :)任何想法将不胜感激:)
When I write my function I get an error "cannot convert 'string to char*' in initiliazation" my function looks like this:当我编写我的函数时,出现错误“无法在初始化中将 'string 转换为 char*'”我的函数如下所示:
int convert(String x){
char *str = x;
int hour; int minute;
sscanf(str, "%d:%d", &hour, &minute);
return hour;
}
convert(time) //time is a String for example 23:0
Since the string is in a particular format ([hour]:[min]), you can use sscanf()
to scan the string.由于字符串采用特定格式 ([hour]:[min]),您可以使用
sscanf()
来扫描字符串。 Since the string is in an expected format, this would be the easiest to do.由于字符串采用预期格式,因此这将是最容易做到的。 Otherwise you'd use the other methods described by everyone else.
否则,您将使用其他人描述的其他方法。
char *str = "23:0";
int hour, min;
sscanf(str, "%d:%d", &hour, &min);
/* hour = 23
min = 0
*/
After that you can do the math that you need and spit the results back out to a buffer.之后,您可以进行所需的数学运算并将结果返回到缓冲区。
char buf[100];
hour = (hour + 6) % 24;
snprintf(buf, 100, "%d:%d", hour, min);
There are simple functions for these simple tasks in the standard library.标准库中有针对这些简单任务的简单函数。 Look up
atoi()
and atof()
for string-to-number conversion, and sprintf()
for number to string.查找
atoi()
和atof()
用于字符串到数字的转换,以及sprintf()
用于数字到字符串的转换。
Edit : example.编辑:示例。 Code:
代码:
#include <stdlib.h>
#include <stdio.h>
int main() {
char string[10];
int n1, n2, result;
n1 = atoi("23");
n2 = 6;
result = (n1 + n2) % 24;
sprintf(string, "%d", result);
printf("Result: %s\n", string);
return 0;
}
stdout:标准输出:
Result: 5
Cheers!干杯!
Sounds like you need a few things done at once (even though this really sounds like a homework assignment).听起来您需要同时完成几件事(尽管这听起来确实像是一项家庭作业)。 The very basic example would be:
非常基本的例子是:
char *x = "23.0";
char *y = "6.0";
float result = atof(x) + atof(y);
float result_24h = result % 24; // Modulo to get remainer only
char result_str[32]; // bad bad form, but good enough for this example
sprintf(result_str,"%f",result_24h);
At least something along those lines, written off the top of my head so apologies in advance for any typos/syntax errors;至少有一些类似的东西,写在我的头上,所以提前为任何拼写错误/语法错误道歉;
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