搜索并更新* .txt文件中的1行-C语言

Question

I'm trying to work on files. I need to manage a *.txt file, i have to search a specific line using a keyword, and then edit some field of this line.

MyFile.txt contains:

Names points wins loss tie

 Mark 4 1 0 1
 Kevin 6 2 1 0
 Phill 10 3 0 1
 Tony 13 4 1 1
 Dan 12 3 2 3
 -END-

Where: Names are my keyword and i have to edit points, wins, loss and tie.

void Update (int Result, char User[15])
{
    struct  Giocatore Player;
    int temp;
    FILE *fp;


    fp=fopen("MyFile.txt","r+");
    if(fp==NULL)
        {
            printf("ERROR.");
       }
    else
        {
            //reading first line of txt
            fscanf(fp,"%s %d %d %d %d",Player.Name,&Player.pts,&Player.wins,&Player.loss,&Player.tie);
            do
                {
                    if(strcmp(Player.Name, User)==0) //finding the username got from main.
                        {
                            if(Result==1) //win root
                                {
                                    Player.Wins++;
                                    Player.pts=(Player.wins*3)+Player.tie;
                                    fprintf(fp,"%s %d %d %d %d",Player.Name,Player.pts,Player.wins,Player.loss,Player.tie);
                                }
                            else if(Result==0) //Tie root
                                {
                                    Player.tie++;
                                    Player.pts=(Player.wins*3)+Player.tie;
                                    fprintf(fp,"%s %d %d %d %d",Player.Name,Player.pts,Player.wins,Player.loss,Player.tie);
                                }
                            else if(Result==2) //loss root
                                {
                                    Player.loss++;
                                    fprintf(fp,"%s %d %d %d %d",Player.Name,Player.pts,Player.wins,Player.loss,Player.tie);
                                }
                        }
                    fscanf(fp,"%s %d %d %d %d",Player.Name,&Player.pts,&Player.wins,&Player.loss,&Player.tie);

                    temp=strcmp(Player.Name,"-END-");

                    } /* end while*/
                while(temp!=0);
            fclose(fp);
        }

}

Im using this code i've made but it doesn't work, I'm able to find the username but i'm not able to update it.

Thanks for helping

Answer 1

You can save the line number and then use the line number to write a copy of the file with the new contents.

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

struct Giocatore {
    char Name[15];
    int pts;
    int wins;
    int loss;
    int tie;
    int Wins;
};

int replaceline(int lineNum, char *replacement) {
    FILE *fp, *fc;

    int count = 0;  //count number lines in source file.
    int ch;   //temporary place to store character of source file(one at a time).
    int edited = 0;  //0=false and 1=true
    char *t;   //temporary place to store input which you want to be replaced with error in text file.


    fp = fopen("MyFile.txt", "r");
    fc = fopen("output.txt", "w");

    if (fp == NULL || fc == NULL) {
        printf("\nError...cannot open/create files");
        return 1;
    }


    while ((ch = fgetc(fp)) != EOF) {
        if (ch == '\n')
            count++;
        if (count == lineNum - 1 && edited == 0) {


            if (count == 0)
                fprintf(fc, "%s\n", replacement);
            else
                fprintf(fc, "\n%s\n", replacement);

            edited = 1;

            while ((ch = fgetc(fp)) != EOF) {
                if (ch == '\n')
                    break;
            }
        }
        else
            fprintf(fc, "%c", ch);
    }
    fclose(fp);
    fclose(fc);

    if (edited == 1)
        printf("\nCongrates...Error Edited Successfully.");
    else
        printf("\nLine Not Found");

    return 0;
}


void Update(int Result, char User[15]) {
    struct Giocatore Player;
    int temp;
    FILE *fp;
    int line = 0;
    char ch[15];
    fp = fopen("MyFile.txt", "r+");
    if (fp == NULL) {
        printf("ERROR.");
    }
    else {
        //reading first line of txt
        fscanf(fp, "%s %d %d %d %d", Player.Name, &Player.pts, &Player.wins, &Player.loss, &Player.tie);
        do {
            line++;
            printf("Player name %s ", Player.Name);
            if (strcmp(Player.Name, User) == 0) {
                if (Result == 1) {
                    Player.wins++;
                    Player.pts = (Player.wins * 3) + Player.tie;

                    sprintf(ch, "%s %d %d %d %d", Player.Name, Player.pts, Player.wins, Player.loss, Player.tie);
                    printf("%s\n", ch);
                    break;


                }
                else if (Result == 0) //Tie root
                {
                    Player.tie++;
                    Player.pts = (Player.wins * 3) + Player.tie;

                }
                else if (Result == 2) //loss root
                {
                    Player.loss++;

                }
            }
            fscanf(fp, "%s %d %d %d %d", Player.Name, &Player.pts, &Player.wins, &Player.loss, &Player.tie);

            temp = strcmp(Player.Name, "-END-");

        } /* end while*/
        while (temp != 0);
        fclose(fp);

        replaceline(line, ch);
    }

}

int main(void) {
    Update(1, "Kevin");
    return 0;
}

File MyFile.txt

Mark 4 1 0 1
Kevin 6 2 1 0
Phill 10 3 0 1
Tony 13 4 1 1
Dan 12 3 2 3
-END-

File output.txt after program runs (Kevin's score was updated)

Mark 4 1 0 1
Kevin 9 3 1 0
Phill 10 3 0 1
Tony 13 4 1 1
Dan 12 3 2 3
-END-