凱撒密碼在C

Question

在這個凱撒密碼我如何讓它讀取空格，特殊字符（！@＃$ * ...）和數字，並保持它們原樣打印出來？另外我在fgets while循環的末尾放了一個fprintf（file2，「\ n」），它確實開始一個新行，但它總是在前一行的末尾打印出一個奇怪的字符。

#include <stdio.h> 

int main (int argc, char *argv[]) { 

char caesar[256]; 
int shift; 
FILE *file1=fopen(argv[1],"r"); 
FILE *file2=fopen(argv[2],"w"); 

sscanf(argv[3], "%d", &shift); 


while(fgets(caesar,sizeof(caesar),file1)!=NULL){ 
int i = 0; 
while (caesar[i] != '\0') { 
    if (((caesar[i] + shift) >= 65 && (caesar[i] + shift) <= 90)||((caesar[i] + shift) >= 97 && (caesar[i] + shift) <= 122)) { 
     caesar[i] += (shift); 
     } 
    else { 
     caesar[i] += (shift - 26); 
     } 
     i++; 
} 
fprintf(file2,"%s", caesar); 
fprintf(file2,"\n"); 
} 
return 0; 
} 

Answer 1

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

int main (int argc, char *argv[]) { 
    char caesar[256]; 
    int shift; 
    FILE *file1=fopen(argv[1],"r"); 
    FILE *file2=fopen(argv[2],"w"); 

    sscanf(argv[3], "%d", &shift); 

    while(fgets(caesar,sizeof(caesar), file1)!=NULL){ 
     char ch; 
     int i = 0; 
     for(i = 0; (ch=caesar[i]) != '\0'; ++i) { 
      if (isalpha(ch)) {//Only alphabet 
       char a, z; 
       if(isupper(ch)){ 
        a = 'A'; z = 'Z'; 
       } else { 
        a = 'a'; z = 'z'; 
       } 
       caesar[i] += shift;//this depend on the sequence of character codes. 
       if(caesar[i] > z){ 
        caesar[i] = a + caesar[i] - z - 1; 
       } 
      } 
     } 
     fprintf(file2, "%s", caesar); 
    } 
    return 0; 
}