How to extend my multiple loop conditions? - c

Question

My code
#include <stdlib.h>
#include <stdio.h>
int main()
{
int i=0;
int j=0;
size_t count=0;
float numbers[20][100];
float velocity[21][101];
char *line = NULL;
FILE *myFile;
myFile = fopen("vel.txt", "r");
if (myFile == NULL)
{
printf("Error Reading File\n");
exit (0);
}
while(i < 20 && getline(&line, &count, myFile)!=-1) {
int len = 0, pos = 0;
j = 0;
while(j < 100 && 1 == sscanf(line + pos, "%f%n", &numbers[i][j++], &len))
pos += len;
i++;
}
free(line);
fclose(myFile);
i=1;
for( j = 0; j < 101; j++ )
{
if( j == 1 )
{
velocity[i][j]=numbers[i][j];
}
else if ( j == 101 )
{
velocity[i][j]=numbers[i][j];
}
else
{
velocity[i][j]=(numbers[i][j-1]+numbers[i][j])/2;
}
}
for (j=0 ; j<101 ; j++) {
printf("\n%f", velocity[i][j]);
}
}
I need to calculate velocities for 21,101 two dimensional mesh.If i==1 ,that is my code above and works fine.The sam conditions apply if i==21.But for all other values (2 to 20) calculations are different.How should I change
if( i== from 2 to 20 &&j == 1 )
{
do something
}
else if (i== from to to 20 && j == 101 )
{
do something 2
}
else(means i goes from 2,20 j goes from 2,100)
{
do something 3
}

Answer 1

Do you want something like this: if(i >= 2 %% i <= 20)? Means: 2 <= i <= 20 or if i is greater or the same as 2 and i is lower or the same as 20 it is true.
If your example:
if(i >= 2 && i <= 20 && j == 1)
{
//do something
}
else if(i >= 2 && i <= 20 && j == 101)
{
//do something 2
}
else if(i >= 2 && i <= 20 && j >= 2 && j <= 100) //means i goes from 2,20 j goes from 2,100
{
//do something 3
}
or is there anything I missed?