c - 为什么没有打印任何内容？ C语言编程

Question

我正在制作一个程序，它从 congress.txt 获取字符，将它们全部大写，然后“将它们移动两个字符”，(A 到 C)(Z 到 B)。但没有打印任何内容，我主要关心的是我的数组是否正确存储并传递给不同的函数。

这是congress.txt中的内容:

Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the government for a redress of grievances.

#include<stdio.h>

int processFile(int *store);
int cipher(int *store, int *code);
int outputCode(int *code);

int main(void){
    int store[300], code[300], i;

    processFile(store);
    cipher(store, code);
    outputCode(code);
    getchar();
    return 0;
}

void processFile(int *store){
    int i, a = 0;
    FILE *f = fopen("congress.txt", "r");

    for (i = 0; a != EOF;){
        fscanf(f, "%c", &a);        //store character in a
        if (a <= 'Z' && a >= 'A'){  //store uppercase letters
            store[i] = a;
            i++;
        }
        if (a <= 'z' && a >= 'a'){  //store lowercase letters as uppercase
            store[i] = a - 32;
            i++;
        }
    }
    i++;
    store[i] = '\0';
}

void cipher(int *store, int *code){
    int i;

    for (i = 0; store[i] != 0; ++i){
        if (store[i] <= 'X' && store[i] >= 'A'){    //tests to see if the letter is between A and X
            code[i] = (char)(store[i] + 2);         //shifts letter by two characters
        }
        if (store[i] >= 'Y' && store[i] <= 'Z'){
            code[i] = (char)(store[i] - 24);        //shifts Y and Z to A or B respectively
        }
    }
}

void outputCode(int *code){
    int i, a, b;
    for (a = 0; code[a] != 0; ++a){
        if (!(a % 50)){                             //makes a newline every 50 characters
            printf("\n");
        }
        for (b = 0; code[a] != 0 && b <= 5; ++b){   //prints chunks of 5 characters then makes a space
            printf("%c", code[a]);
        }
        printf(" ");
    }

}

Answer 1

您的代码有几个问题 - 您的编译器会提示其中许多问题。

首先 - 对于声明为 int 的函数，您没有返回值。只需让它们void，或者返回一些东西。

第二 - 您声明 int a; 但继续像 char 一样使用它。声明你如何使用它。

第三 - 文件结尾测试是通过 feof(f) 完成的，而不是 a != EOF。

第四 - 当你输出代码时，你需要增加a，否则你会得到相同的值五次:

VVVVVV JJJJJJ KKKKKK UUUUUU KKKKKK UUUUUU UUUUUU

等等

第五 - 你的打印例程不能保证它会停止 - 如果你有一个 '\0' 后跟其他垃圾，你将打印更多垃圾(除非它发生在多个垃圾上) 5)。您需要用零填充密码。

所以 - 工作代码:

#include<stdio.h>

int processFile(int *store);
int cipher(int *store, int *code);
int outputCode(int *code);

int main(void){
    int store[300], code[300], i;

    processFile(store);
    cipher(store, code);
    outputCode(code);
    printf("\n=====\n\n");
    return 0;
}

int processFile(int *store){
    int i;
    char a = 0;
    FILE *f = fopen("congress.txt", "r");

    for (i = 0; !feof(f) && i<299;){
        fscanf(f, "%c", &a);        //store character in a
        if (a <= 'Z' && a >= 'A'){  //store uppercase letters
            store[i] = a;
            i++;
        }
        if (a <= 'z' && a >= 'a'){  //store lowercase letters as uppercase
            store[i] = a - 32;
            i++;
        }
    }
    store[i]='\0';
    return 0;
}

int cipher(int *store, int *code){
    int i;

    for (i = 0; store[i] != 0; ++i){
        if (store[i] <= 'X' && store[i] >= 'A'){    //tests to see if the letter is between A and X
            code[i] = (char)(store[i] + 2);         //shifts letter by two characters
        }
        if (store[i] >= 'Y' && store[i] <= 'Z'){
            code[i] = (char)(store[i] - 24);        //shifts Y and Z to A or B respectively
        }
    }
    for(; i<300; i++) code[i]=0; // pad with zeros
    return 0;
}

int outputCode(int *code){
    int i, a, b;
    for (a = 0; code[a] != 0; ++a){
        if (!(a % 50)){                             //makes a newline every 50 characters
            printf("\n");
        }

        for (b = 0; code[a] != 0 && b <= 5; ++b){   //prints chunks of 5 characters then makes a space
            printf("%c", code[a++]);
        }
        printf(" ");
    }
return 0;
}