Paraoblic Path

I have a task that I have to submit immediately.OK,here are the instructions.
Creating a programme for parabolic path/parabolic motion.
-The object is shot from the ground and there must be 4 input datas : the duration of time (t),the angle,initial velocity and the time interval of the displacement(delta t).
-The output should be the displacement in both the x and y direction.
- projection time is set to 0
- the position after t seconds is calculated by delta t second intervals(t and delta t is also input after the program runs).
- the result is output to the file, use Excel to make graph with it

I am having problems with writing the equations correctly and also with t and delta t

Here's what I have done so far.Someone correct me please.

Code:

#include <stdio.h>
#include <math.h>
#define g 9.8
int main()
{
double t, x, y, angle, Vo, deltat;
char buf[256];
int i;
FILE* fp;
printf( "t = " );
fgets( buf, 256, stdin );
sscanf( buf, "%lf\n", &t );
printf( "deltat = " );
fgets( buf, 256, stdin );
sscanf( buf, "%lf\n", &deltat );
printf("initial velocity = ");
sscanf( buf, "%lf\n", &Vo );
fgets( buf, 256, stdin );
printf( "angle = " );
sscanf( buf, "%lf\n", &angle );
fgets( buf, 256, stdin );

fp = fopen( "z:\\FreeFall.txt", "w" );
for( i = 0; i < t; 'i+=deltat' ) {
y = Vo*sin(angle)*deltat - ( g / 2.0 ) *deltat * deltat;
x = Vo*cos(angle)*deltat;


printf( "i= %f, y= %f ,x= %f\n", t, y, x );
fprintf( fp, "i=, %f, y=, %f ,x= %f\n", t, y, x );
}
fprintf( stderr, "File z:\\FreeFall.txt was created\n" );
fclose( fp );
return 0;
}

Here's the results.It came out endless and with weird results

Code:

for( i = 0; i < t; 'i+=deltat' ) {

Why would you have quotes around the increment statement in this loop?

Also fix your indentation. I'm not wasting my time matching up your for loop start and end brackets when you're supposed to make it clear by formatting the code properly.
I'm not picking on you, I try to tell everybody this, even if their code only has a few braces total, in it.