英文:
in dev c++ my library is missing how to install it
问题
//my code is
#include <stdio.h>
int main() {
char txt[] = "xyz";
printf("%d", strlen(txt));
return 0;
}
//error is strlen is not declared in this scope
//it should work my code is correct
英文:
//my code is
#include <stdio.h>
int main() {
char txt[] = "xyz";
printf("%d", strlen(txt));
return 0;
}
//error is strlen is not declared in this scope
//it should work my code is correct
答案1
得分: 2
https://en.cppreference.com/w/c/string/byte/strlen 说:
> 定义在头文件 <string.h>
P.S. 它还指出返回类型是 size_t，这是无符号的，而 https://en.cppreference.com/w/c/io/fprintf 说 size_t 的 printf 格式符是 z，所以格式字符串应该是 "%zu"。
英文:
https://en.cppreference.com/w/c/string/byte/strlen says:
> Defined in header <string.h>
P.S. It also says that the return type is size_t, which is unsigned, and https://en.cppreference.com/w/c/io/fprintf says that the printf specifier for size_t is z, so the format string should be "%zu".
答案2
得分: 2
问题
- 你忘记了包含
<string.h>头文件以使用strlen()函数。更多信息请查看这里。 strlen的返回类型是size_t而不是int，因此应该使用%zu来格式化输出。
修复:
#include <stdio.h>
#include <string.h> // 你遗漏的头文件
int main(void) {
char txt[] = "xyz";
printf("%zu", strlen(txt));
return 0;
}
英文:
issues
- You're missing the <string.h> header for
strlen(). More info here. - The return type of strlen is that of size_t not int so use %zu for the format
fix:
#include <stdio.h>
#include <string.h> // The header you were missing
int main(void) {
char txt[] = "xyz";
printf("%zu", strlen(txt));
return 0;
}
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