How to open a website with % in a program?

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Windows

I just want to create a program to open specific webpage.
For example open the website below:
http://xxxx/cgi-bin/main-cgi?json=%7b%2cmd%2%3a%2c%2bEnabled%2%3a%7d
xxxx means something you need to enter

What I have tried:

1.I have tried in bat.

@set /p ip=please enter ip:

@start explorer.exe "http://%ip%/cgi-bin/main-cgi?json=%%7b%22cmd%22%3a654%2c%22bEnabled%22%3a1%7d"

@exit

2.I have tried in C++

#include<stdio.h>
#include<windows.h>
int main() {
	ShellExecute(NULL, "open", "http://IP/cgi-bin/main-cgi?json=%7b%%22cmd%22%3a654%2c%22bEnabled%22%3a1%7d", NULL, NULL, SW_HIDE);
	return 0;
}

But as you know, % don't show as a character.
What can I do? Please help.