c - 将文本从文件打印到屏幕

Question

假设我在文件中放入一些文本，关闭文件后将其打印到屏幕上的最快方法是什么？

例如，在下面的函数中，我使用 printf 将一些文本放入文件中。 我希望该文本输出到屏幕。

void calcMemoryOfVariables(char str[], char* filename) 
{
    int i = 0, j = 0;
    int temp = 1;
    int size;
    char* tempChar = (char*)malloc((strlen(str))*sizeof(tempChar));
    FILE *f=fopen(filename,"w");
    if (f==NULL)
        exit(1);

    while (str[i]!=' ' || str[i]=='*') //checking the type of the variable//
    {
        tempChar[j] = str[i];
        i++;
        j++;   
    }
    tempChar[j] = '\0';

    size = calcSize(tempChar);  //the size of that variavle in bytes//

    j = 0;
    i++;
    while (str[i] != ';')
    {

        if ((str[i]>='a' && str[i]<='z') || (str[i]>='A' && str[i]<='Z')) // for  variables and arrays//
        {
            while (str[i] != ',' ) 
            {
                if (str[i]==' ')
                {
                    while (str[i]==' ')
                        i++;
                }

                if (str[i] == '[')      //checks if it is an array//
                {
                    printf("%c", str[i]);
                    i++;
                    while (str[i] != ']')
                    {
                        tempChar[j] = str[i]; //copies the value in the string//
                        i++;
                        j++;
                    }

                    tempChar[j] = '\0';
                    temp = strToInt(tempChar); //converting to int in order to valuate the bytes//
                }
                printf("%c", str[i]);
                i++;

                if (str[i]==' ')
                {
                    while (str[i]==' ')
                        i++;
                }
            }
            fprintf(f," requires %d bytes \n", temp*(sizeof(temp)));
        }


        if (str[i] == '*')           //for pointers//
        {
            while (str[i] != ',' && str[i] != ';')
            {
                printf("%c", str[i]);
                i++;
                if (str[i]==' ')
                {
                    while (str[i]==' ')
                        i++;
                }
            }
            fprintf(f," requires %d bytes \n", 4);
        }
        if (str[i] != ';')
            i++;
    }

    fclose(f);
}

Answer 1

您可以使用 sprintf 将文本写入数组。这将允许您将文本写入文件并将其打印在屏幕:

char output[16];
FILE* fd = fopen("output.txt", "w"); 
sprintf(output, "%s", "Output Test\n");
printf("%s", output);
fwrite(output, 1, strlen(output), fd);
fclose(fd);