将一行存储为字符串，然后在C代码中输出

Question

Is it possible to store a line of printed statement as string and output the line later in other part ?

If no then is there other method ? Provided that the line printed is not entered by user but need to use it to display at other part.

Tried google but still no clue about it.

I'm using Visual Studio 2010 and what I had tried so far is :

#include<stdio.h>
int main()
{
int choice;
char line[20];    //variable to store the line 
printf("Enter your choice\n");
scanf("%d", &choice);
switch(choice){
case 1:
    printf("You had selected first choice\n");    //this line wanted to be store as string and output at bottom 
line[20]="You had selected first choice"; // error C2440
scanf("%s", &line); // probably I could use this to store the line ? 
break;

default:
    exit(0);
}
printf("%s", line); // display the line which has been store in above 
return 0;
}

Answer 1

You have three problems, the first is that line[X] is a single character and you try to assign a string to it ( line[20] is out of bounds by the way). The second problem is that you can't assign to an array, you can initialize an array at definition, or you can copy to it, using eg strcpy . The third error is that the string you try to copy to the array is much longer than 20 characters.

Answer 2

• Do not access line[20] , which is out-of-range.
• 20-byte array is too small to store "You had selected first choice" , which is 29-character and 30-byte (incluting terminating null character) long.
• scanf("%s", &line); is undefined behavior because of type mismatch: "%s" expect char* and &line is char(*)[20] .

You can use strcpy() to copy null-terminated strings.

Fixed code:

#include<stdio.h>
#include<stdlib.h> // for using exit()
#include<string.h> // for using strcpy()
int main(void)
{
    int choice;
    char line[64];    //variable to store the line 
    printf("Enter your choice\n");
    scanf("%d", &choice);
    switch(choice){
    case 1:
        printf("%s\n", strcpy(line, "You had selected first choice"));
        break;

    default:
        exit(0);
    }
    printf("%s", line); // display the line which has been store in above 
    return 0;
}

Answer 3

// In general do a formatted output to char array,  
// and use it as you like.  
sprintf(line, "%s", "You had selected first choice\n");  
printf("%s", line);