我试图从字符串(char*)中取出所有数字......
这是我现在所拥有的:
// Take numbers out of username if they exist - don't care about these
char * newStr;
strtoul(user, &newStr, 10);
user = newStr;
我的理解是 strtoul 应该将字符串转换为无符号长整型。非数字的字符被放入传入的指针(第二个参数)中。当我将用户重新分配给 newStr 并打印它时,字符串保持不变。为什么是这样?有谁知道更好的方法?
从文档示例:
#include <stdio.h>
#include <stdlib.h>
int main()
{
char str[30] = "2030300 This is test";
char *ptr;
long ret;
ret = strtoul(str, &ptr, 10);
printf("The number(unsigned long integer) is %lu\n", ret);
printf("String part is |%s|", ptr);
return(0);
}
让我们编译并运行上面的程序,这将产生以下结果:
The number(unsigned long integer) is 2030300
String part is | This is test|
char* RemoveDigits(char* input)
{
char* dest = input;
char* src = input;
while(*src)
{
if (isdigit(*src)) { src++; continue; }
*dest++ = *src++;
}
*dest = '\0';
return input;
}
Test:
int main(void)
{
char inText[] = "123 Mickey 456";
printf("The result is %s\n", RemoveDigits(inText));
// Expected Output: " Mickey "
}
数字已被删除。
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