c - 我正在尝试将 char 打印到输出文件，但是，我的编译器说我正在打印 int

Question

Pass1.c: In function ‘main’:

Pass1.c:53:6: warning: format ‘%s’ expects argument of type ‘char *’, but argument 3 has type ‘int’ [-Wformat=]

 fprintf(ofp,"%s", curr);

这就是我遇到的确切错误。我正在尝试使用 fprintf 将 curr 打印到输出文件。我运行该程序并尝试从我的输入文件输出，但我最终遇到了段错误。我是第一次使用 c，不知道发生了什么。这是我的代码:

#include <stdio.h>
#include <ctype.h>

void main() {
    int qflag, zflag, punctflag;
    int skip;
    int orgChar, decChar, codeChar; //# of original characters, decoded characters, and code sequences
    double perDec;
    FILE *ifp, *ofp; //input & output file pointers 
    char filename[30], curr; // filename and the current character input from the file

    printf("Enter the filename to be scanned:  ");   // ask user for filename
    scanf("%s", filename);   //user filename input

    ifp = fopen(filename, "r"); // open the file as read-only
    ofp = fopen("output.txt", "w"); // open output file as write-only

    while ((curr = getc(ifp)) != EOF) {    // get the next char and as long as it is not the EOF, continue

        if (qflag && isdigit(curr)) { //qflag is true and is digit is true
            skip = (int) curr - 48; //skip # of digits 
            codeChar++; //add to coded char index
            qflag = 0; //qflag now flase 
        } else if (qflag) {  //if q isnt followed by a interger
            fprintf(ofp, "q"); //print q
            decChar++; //added to the decoded index
            qflag = 0; //qflag now false
        }

        if (punctflag == 1 && isdigit(curr)) {
            skip = (int) curr - 48;
            punctflag = 0;
        }
        //If there is a special case where we have something z^g the else would be here

        if (zflag && ispunct(curr)) {
            punctflag = 1;
            codeChar += 2;
            zflag = 0;
        } else if (zflag) {
            fprintf(ofp, "z");
            decChar++;
            zflag = 0;
        }
        //must put in the X variable!!!!!!!!!!
        if (curr == 'q' || curr == 'Q') {
            qflag = 1;
        } else if (curr == 'z' || curr == 'Z') {
            zflag = 1;
        }

        if (zflag == 0 && qflag == 0 && skip == 0) { //need x here
            fprintf(ofp, "%s", curr); //<------ getting issue here!
            decChar++;
        } else {
            skip--;
        }
    }

    fclose(ifp); //closes input file
    fclose(ofp); //closes output file
}

Answer 1

你的定义是:

char filename[30], curr;

这里 filename 是一个数组，但是 curr 不是。如果你想放一个字符串，这是正确的:

char filename[30], curr[size];

但是你只想放一个字符。在这种情况下，不要触及上面 curr 的定义，而是更改 fprintf 部分，如下所示:

fprintf(ofp,"%c", curr);

%s 不行，因为您要放置一个字符，而不是一个字符串。