Myujth

I was asked to write a program about a traveling man.
The direction of the program:

1. Suppose a man (say, A) stands at (0, 0) and waits for the user to give him the direction and distance to go.




2. The user may enter N E W S for north, east, west, south, and any value for the distance.




3. When the user enters 0 as direction, stop and print out the location where the man stopped

My Code:

#include <stdio.h>

int main() 
float x=0,y=0;
char dir;
float mile;

while(1)

 printf("Enter input direction as N,S,E,W (0 to exit): ");
 scanf("%c",&dir); 

 if(dir == '0')
 break;
 if(dir != 'N' && dir != 'S' && dir != 'E' && dir != 'W')

 printf("Invalid Direction, re-enter n");
 continue;
 

 printf("Input mile in %c dir: ",dir);
 scanf("%f",&mile);
 if(dir == 'N')
 y+=mile;
 
 else if(dir == 'S')
 y-=mile;
 
 else if(dir == 'E')
 x+=mile;
 
 else if(dir == 'W')
 x-=mile;
 

 printf("nCurrent position of A: (%4.2f,%4.2f)n",x,y);
return 0;

But when I run the program after the first two inputs, it prints invalid outputs in the valid inputs.

output:

So, I found your problem: When you were pressing "Enter" after you entered the "miles", that "Enter" got registered as input, as a 'n' character. I have a solution here for you, but if you don't prefer it, just make a special case in which you ignore the 'n' character. Something like else if (dir == 'n') continue;. I suspected this might be the problem but I confirmed it once I printed that "invalid character".

int main() 


 float x = 0, y = 0;
 char dir;
 float mile;

 do 
 

 printf("Enter input direction as N,S,E,W (0 to exit): ");
 scanf("%c", &dir);

 switch (dir)
 

 case 'N':
 printf("Input mile in %c dir: ", dir);
 scanf("%f", &mile);
 y += mile;
 break;
 case 'S':
 printf("Input mile in %c dir: ", dir);
 scanf("%f", &mile);
 y -= mile;
 break;
 case 'E':
 printf("Input mile in %c dir: ", dir);
 scanf("%f", &mile);
 x += mile;
 break;
 case 'W':
 printf("Input mile in %c dir: ", dir);
 scanf("%f", &mile);
 x -= mile;
 break;
 case 'n':
 break;
 case '0':
 break;
 default:
 printf("Invalid Direction, re-enter; You entered: %c n", dir);
 break;
 

 while (dir != '0');

 printf("nCurrent position of A: (%4.2f, %4.2f)n", x, y);

 return 0;

Its a classic mistake of OR vs AND.
It should be

if(dir != 'N' && dir != 'S' && dir != 'E' && dir != 'W') . 

For eg if a user inputs 'N', in that case the if statement will still return success because its != 'S' and the if condition has a OR.

Edit: (Following @usr2564301 's advice.)

Add a space before scanf input %c.

scanf(" %c",&dir);

Check link for more explanation.