Struggling to search an array of structs in a file by integer - c

Question

I'm in the middle of a major assignment and I'm really struggling to be able to pull a structure from an array in a file. I'm not sure where to go from here in my code as I don't have much experience working with C.
I am trying to search the file looking for "Robot_Number" (integer to far left) then print all of that specific robots information. My code compiles and runs but won't print anything from the while loop (Ln57-66). There are also no apparent problems with the .txt file.
My .txt file is laid out like this:
1 Bender 2054 30.500000 80 60 0.000000
2 Crusher 1979 15.000000 86 80 0.000000
3 Sprinter 2042 45.000000 41 30 0.000000
4 Vulc4n 2178 47.000000 90 50 0.000000
My code:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define RobMax 10
typedef struct {
int Robot_Number;
char Robot_Name[20];
int Year_Manufactured;
float Top_Speed;
int Strength;
int Mass;
float Best_Score;
}robot_t;
int main(){
int targetNumber;
int RobCounter = 4;
//create an array of struct,
robot_t robot_info[RobCounter] =
{{1, "Bender", 2054, 30.5, 80, 60, 0},
{2, "Crusher", 1979, 15, 86, 80, 0},
{3, "Sprinter", 2042, 45, 41, 30, 0},
{4, "Vulc4n", 2178, 47, 90, 50, 0}};
//opening a file for reading and writing
FILE* file =fopen("Robot.txt", "r+w");
if(file ==NULL){
printf("ERROR: file failed to open!\n");
exit(-1);
}
/*//Initialising the .txt file, first time only
for (i=0; i<4; i++){
fprintf(file, "%d %s %d %f %d %d %f\n",
robot_info[i].Robot_Number,
robot_info[i].Robot_Name,
robot_info[i].Year_Manufactured,
robot_info[i].Top_Speed,
robot_info[i].Strength,
robot_info[i].Mass,
robot_info[i].Best_Score);
}*/
printf("you selected search a robot by number. (Type 0 to view all avalible robots)\n");
scanf("%d", &targetNumber);
int RNo, YM, S, M;
char RNa[20];
float TS, BS;
if (targetNumber != 0){
printf("Robot ID: %d's information:\n", targetNumber);
while( fscanf(file, "%d%19s%d%f%d%d%f", &RNo, RNa, &YM, &TS, &S, &M, &BS) ==2) {
robot_info[targetNumber].Robot_Number = RNo;
strcpy(robot_info[targetNumber].Robot_Name, RNa);
robot_info[targetNumber].Year_Manufactured = YM;
robot_info[targetNumber].Top_Speed = TS;
robot_info[targetNumber].Strength = S;
robot_info[targetNumber].Mass = M;
robot_info[targetNumber].Best_Score = BS;
printf("Num: %d, Name: %19s, Manufactured: %d, Top Speed: %f, Strength: %d, Mass: %d, Best Score: %f.", RNo, RNa, YM, TS, S, M, BS);
}
}
fclose(file);
return 0;
}

Answer 1

Some notes to consider, as stated in the comment section, too:
Why do you have an array of structs with robot info, when you intend to read them from a file?
Why open the file with r+w when you're really just reading from it?
So lets suppose, that you do not have those information about the robots and you only want to read the file. If this was the original intent, here is a snippet, that'll probably help you.
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define RobMax 10
typedef struct {
int Robot_Number;
char Robot_Name[20];
int Year_Manufactured;
float Top_Speed;
int Strength;
int Mass;
float Best_Score;
}robot_t;
int scan_file(const char* fname, robot_t* robot_info, const int N)
{
int counter = 0;
// opening a file for reading
// Note the change in file open mode as you
// do not need to write it
FILE* file = fopen(fname, "r");
if(file == NULL)
{
printf("ERROR: file failed to open!\n");
return 0;
}
int RNo, YM, S, M;
char RNa[20];
float TS, BS;
// Note the change in scan format - you need to include the correct delimiters
// in your case the white spaces. Also changed 2 -> 7 as you'd expect 7 values
// to be read and not 2
int scanres;
while((scanres = fscanf(file, "%d %19s %d %f %d %d %f", &RNo, RNa, &YM, &TS, &S, &M, &BS)) == 7 && scanres != EOF)
{
// if we reached maximum capacity
if (counter >= N)
break;
robot_info[counter].Robot_Number = RNo;
strcpy(robot_info[counter].Robot_Name, RNa);
robot_info[counter].Year_Manufactured = YM;
robot_info[counter].Top_Speed = TS;
robot_info[counter].Strength = S;
robot_info[counter].Mass = M;
robot_info[counter].Best_Score = BS;
printf("SCANNED: Num: %d, Name: %19s, Manufactured: %d, Top Speed: %f, Strength: %d, Mass: %d, Best Score: %f.\n", RNo, RNa, YM, TS, S, M, BS);
++counter;
}
fclose(file);
return counter;
}
// gets the robot's index in the robots array by ID
int get_roboti_by_id(const int ID, const robot_t* robots, const int N)
{
for (int i = 0; i < N; ++i)
{
if (robots[i].Robot_Number == ID)
{
return i;
}
}
return -1;
}
void print_info(const robot_t* info)
{
printf("Num: %d, Name: %19s, Manufactured: %d, Top Speed: %f, Strength: %d, Mass: %d, Best Score: %f.",
info->Robot_Number, info->Robot_Name, info->Year_Manufactured, info->Top_Speed, info->Strength, info->Mass, info->Best_Score);
}
int main()
{
int targetNumber;
int RobCounter;
// create an array of struct,
robot_t robot_info[RobMax];
printf("you selected search a robot by number. (Type 0 to view all avalible robots)\n");
scanf("%d", &targetNumber);
// scans the whole file populated with robots
RobCounter = scan_file("robots.txt", robot_info, RobMax);
if (targetNumber != 0)
{
int robot_index = get_roboti_by_id(targetNumber, robot_info, RobCounter);
if (robot_index >= 0)
{
print_info(&robot_info[robot_index]);
printf("\n");
}
else
{
printf("There is no such robot with index: %d\n", targetNumber);
}
}
else
{
for (int i = 0; i < RobCounter; ++i)
{
print_info(&robot_info[i]);
printf("\n");
}
}
return 0;
}
If you spot any mistakes or this was not what you needed, please do not hesitate to correct me. Any suggestions are appreciated!