Compile your code
You have to look at the compilation errors and fix them.
Also, when you share you code, share the whole content, not just a fragment. Includes, variables, functions and other declarations, etc are also important.
Problems
Strings
When you want to read or print strings, you have to use the %s format. Also, store strings in char buffers (see name below). Only problem is that in a buffer you cannot store longer strings than the size of the buffer.
Decimals
Decimals (e.g. int) should be used with the %d format.
A possible solution
#include <stdio.h>
int main()
{
char name[100];
int gender;
printf("Enter your name: ");
scanf("%s", name);
printf("\nEnter your gender (1 for male, 0 for female): ");
scanf("%d", &gender);
printf("\n");
if (gender == 1)
{
printf("Hello Mr. %s\n", name);
}
else if (gender == 0)
{
printf("Hello Ms. %s\n", name);
}
else
{
printf("Unknown gender code: %d\n", gender);
}
return 0;
}